Ice accretion by the impact of supercooled water drops, or mixtures of these drops with ice, onto an aircraft in flight is a hazard referred to as icing. Aircraft certified to fly in icing conditions like airliners, currently have simplistic icing detection probes. Aircraft certification specifications recently developed in response to the discovery that ice accretion by the impact of supercooled large droplets (SLDs) has caused many aircraft accidents imply the need for an icing detection system (IDS) capable of discerning between ordinary icing conditions and the more hazardous SLD icing conditions. It is desirable that these new IDS be capable of measuring both the ice accretion onto the aircraft and the icing-hazard potential of the atmosphere around the aircraft. We report the development and flight test of an IDS consisting of a microwave resonator unit to measure ice accretion onto the aircraft and an optical unit to estimate the icing-hazard potential of the atmosphere around the aircraft. The results of flight tests in a jet aircraft with reference scientific measurements indicate that our new IDS is capable of detecting ice accretion in the aircraft and of discriminating between common icing conditions and the more hazardous SLD icing conditions.
Over 30% of temporary aircrew incapacitations are musculoskeletal, with 20% involving the shoulder. The purpose of this study was to analyze return to work (RTW) after shoulder surgery in an aviation-focused surgical practice serving a civilian commercial major airline's crew. This retrospective case series reviewed shoulder surgical procedures performed at a specialized orthopedic practice between 2023-2024, excluding second opinions, conservative treatments, and follow-up cases from other surgeries. Unrestricted and full RTW was defined as the days from surgery to the first day of work resumption. There were 30 patients who underwent shoulder surgery: 19 male pilots (mean age 50.3) and 11 cabin crew (7 females, mean age 36.3; 4 males, mean age 30), with an overall mean cabin crew age of 35.1. The average RTW was 59.2 d. Shoulder dislocations had a mean RTW of 75.7 d, while impingement with acromio-clavicular joint osteoarthritis averaged 55.1 d. Other conditions, including impingement, rotator cuff tears, clavicle fractures, and superior labrum anterior to posterior lesions, ranged from 15-70 d. One complex proximal humerus fracture required 103 d, while two frozen shoulder cases returned after 15 d. This study indicates that most surgically treated shoulder conditions have a mean RTW time of 50-60 d. Shoulder stabilization after dislocation takes 14 d longer, while complex proximal humerus fractures take twice as long. Aviation-focused surgical practices coupled with an aviation-specific musculoskeletal rehabilitation unit facilitate a faster RTW when compared to local regulatory data. Hohmann E, Pieterse R. Aviation-focused shoulder surgery and rehabilitation accelerates return to work in civilian aircrew. Aerosp Med Hum Perform. 2026; 97(7):510-515.
The aeromedical certification of commercial airline pilots relies on periodic, self-disclosure-dependent assessments. However, this reactive model lacks the temporal resolution required to capture the gradual behavioural and physiological perturbations preceding an overt mental health crisis. Concurrently, anonymous epidemiological surveys consistently document subclinical depressive symptoms, insomnia, and burnout among active flight crews. Within the framework of predictive, preventive, and personalised medicine (3PM), these conditions represent suboptimal health states situated in the critical transition zone between health and disease. In this narrative review, we propose a conceptual framework for integrating digital phenotyping and artificial intelligence (AI) into aeromedical mental health monitoring, grounded in the 3PM paradigm. With this aim, we appraise three complementary data streams - including smartphone-derived behavioural markers, wearable-derived physiological signals, and cockpit-derived vocal biomarkers - and examine how aviation-specific confounders modulate their validity. Furthermore, we propose a hybrid federated-plus-on-device AI architecture that reconciles population-level statistical power with individual data sovereignty. Crucially, this framework advances the three constitutive dimensions of 3PM in the aviation context. Regarding prediction, it delivers longitudinally resolved diagnostics capable of detecting health-to-disease trajectories during the prodromal phase, surpassing the temporal limitations of current certification cycles. For prevention, it establishes risk-stratified intervention pathways triggered by deviations from individual baselines, thereby shifting oversight from reactive grounding to pre-emptive peer support. Finally, it affords the personalisation of medical services via on-device AI; by calibrating monitoring to each pilot's specific behavioural baseline, duty patterns, and circadian exposure, it effectively replaces population-normed evaluations with individually tailored longitudinal surveillance.
Large-artery atherosclerosis stroke (LAA) is the main subtype of ischemic stroke. Currently, the diagnosis of LAA is confirmed through magnetic resonance imaging. At present, numerous substances are extensively studied as biomarkers, including metabolites, inflammatory factors, RNA, and more. In this study, we incorporated LAA peripheral blood data from various datasets and employed methods such as differential analysis, GSEA, WGCNA, PPI and machine learning to identify multiple molecules uniquely expressed in LAA. We validated these characteristic genes through qRT-PCR using clinical blood samples. We identified 131 differentially expressed genes in peripheral blood samples of stroke patients through differential analysis, and found through functional enrichment analysis that they are associated with inflammation related signaling pathways, Lysosome, Phagosome, and other related reactions. WGCNA identified the modules most relevant to large-artery atherosclerosis stroke, obtained 50 key genes by taking the intersection, and then used random forest to determine feature genes. The reliability of the results was verified by qRT-PCR. Finally, we constructed lncRNA-mRNA network to evaluate the interaction between lncRNA and mRNA. Our research suggested that PYGL, CLEC4D, LAMP2, and IRS2 can serve as biomarkers for diagnosing LAA, and Lnc-STARD3NL-4:1 may be a key lncRNA RNA regulating multiple LAA related factors.
The aviation industry faces increasing pilot training demands, and reliance on conventional Full Flight Simulators (FFS) limits training capacity. Virtual Reality (VR) offers scalable, remote training opportunities, but its role as a complement to FFS requires empirical validation. In collaboration with Singapore Airlines (SIA) instructor pilots, we developed a VR training prototype for a visual approach into Gimhae International Airport, emphasizing Competency-Based Training and Assessment (CBTA)-based Threat and Error Management (TEM). An empirical study with 39 SIA Boeing 737-MAX 8 type-rated first officers evaluated VR against FFS. An equivalence analysis showed that VR achieved performance outcomes comparable to FFS in 13 of the 16 Observable Behaviors (OBs) and across 4 Competencies. In addition, a comparative analysis indicated measurable performance improvements when VR was used to supplement FFS training. Our results suggest VR can meaningfully complement FFS in targeted competency areas, with future work required to assess its broader integration across additional scenarios and performance metrics.
Clade 2.3.4.4b influenza A(H5N1) viruses have circulated across migratory bird flyways in the United States since 2022, including in Washington, where backyard flock detections have been reported annually. In November 2025, a Washington resident died from acute respiratory failure after receiving a positive influenza A(H5) test result at a hospital laboratory. Washington Public Health Laboratories confirmed influenza A(H5), and genomic sequencing identified influenza A(H5N5) virus (A6 genotype). Polymerase chain reaction testing detected highly pathogenic avian influenza A(H5) virus clade 2.3.4.4b from an apparently healthy backyard flock of ducks and sediment from a watering basin on the patient's property. Six of eight gene segments from the environmental sample and one duck sample (partial neuraminidase segment) were highly genetically similar to the patient's virus sequence. Although existing wild bird surveillance had not detected influenza A(H5N5) virus (A6) in the U.S. Pacific Flyway, introduction via wild birds into the environment of the backyard flock was likely the source of the patient's exposure. The public health investigation identified approximately 135 exposed persons; symptom monitoring and influenza testing detected no additional cases. The overall risk for avian influenza A remains low among the general U.S. population; however, novel avian influenza A virus infection should be considered in persons with symptoms of influenza and potential exposures.
Identification, a cognitive process by which individuals think of themselves as similar to another person, may be associated with distress during traumatic events. This study examined the association of identification with psychological responses among disaster workers not directly exposed to an airline crash. Participants were 421 workers (aged 18-60 [M (SD) = 36.2 (9.9)], 86.4% male, 98.3% White, 71.8% married). Surveys at 2 months (Time 1; T1) and 7 (T2) months post-disaster assessed identification (i.e., extent to which participants identified victims as similar to themselves, a friend, and/or family member), previous disaster exposure, and acute stress and anger/hostility. Linear and logistic regression analyses examined the relationship of identification to psychological responses over time. Approximately 15% of participants reported that they had high levels of acute stress within a week of the airplane crash when assessed 2 months later. Among those with high identification, 30.2% had high acute stress. In multivariable models, adjusting for covariates, greater identification was associated with acute stress and anger/hostility at T1, but not anger/hostility at T2. Identification is associated with high levels of acute stress and anger/hostility in non-exposed individuals. Those with greater identification, regardless of exposure, could be at increased risk of distress and may benefit from early interventions.
As indispensable members of the flight crew for passenger transport on large aircraft, flight attendants are responsible for cabin safety, security, passenger services, and emergency response during flights. As the primary interface between passengers and airlines, their delivery of high-quality service is critical to maintaining passenger loyalty and supporting airlines' sustained prosperity. Enhancing flight attendants' in-flight service performance thus represents a key focus in airline management. This cross-sectional study examined the relationships among spiritual leadership, meaningful work, work engagement, and service performance using a sample of 313 Chinese flight attendants from Tibet Airlines and its branches. Psychological questionnaire surveys and correlation analyses revealed significant positive correlations among all four variables. Bootstrap analyses demonstrated that meaningful work and work engagement not only exert independent mediating effects on the relationship between spiritual leadership and service performance, but also jointly form a sequential mediating chain. Theoretical implications of these findings and practical recommendations for enhancing flight attendants' service performance in airline management are discussed.
Adverse childhood experiences (ACEs) are known risk factors for mental health issues in adulthood. Shift workers, especially those in high-stress roles like aviation, are particularly vulnerable to these mental health conditions. However, limited research has explored the relationship between ACE exposure and mental health in this population. This cross-sectional study used data from the Civil Aviation Health Cohort of China (November to December 2023). Aviation personnel (aged 18-60) reported 11 ACE types, categorized by count and latent class analysis. Mental health symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9), the Generalized Anxiety Disorder-7 (GAD-7), and a single-item screener for depression, anxiety, and suicidal ideation, respectively. The study analyzed 19,137 aviation personnel (61.7% male, mean age 31.7 years). Latent class analysis identified three ACE patterns: low ACE (96.5%), abuse (2.8%), and family dysfunction (0.7%). Notably, 22.6% reported ≥1 ACE and 1.2% reported ≥4, showing a dose-response association with mental health risks. Family dysfunction showed the strongest associations with depression (AOR 5.22, 95% CI 3.80-7.17), anxiety (AOR 3.94, 95% CI 2.82-5.50), and suicidal ideation (AOR 4.46, 95% CI 2.55-7.82). The cross-sectional design precludes causal inference. The reliance on retrospective self-report of ACEs may be subject to recall bias. Potential residual confounding and selection bias further limit generalizability. These findings highlight the need for workplace mental health strategies to support shift workers, particularly those with a history of ACEs. Further research is needed on mechanisms linking ACEs to aviation shift workers' mental health and potential protective factors.
Background: Recessive dystrophic epidermolysis bullosa (RDEB) is a rare inherited disorder characterized by extreme epithelial fragility and progressive cicatrization, frequently leading to severe ocular surface disease and early visual impairment. Surgical interventions such as ocular surface reconstruction (OSR) in childhood are often delayed because of anesthetic risks and concerns regarding recurrence. Consequently, the effectiveness of OSR, including amniotic membrane transplantation (AMT), and its impact on visual development remain poorly documented. Methods: We report a case series of two pediatric patients (three eyes) with genetically confirmed RDEB who underwent single-step OSR using AMT. Clinical outcomes, long-term visual acuity, perioperative management, and histopathological findings were evaluated. Results: Ocular manifestations included corneal epithelial damage, symblepharon, and pseudopterygium extending over the cornea. One patient underwent symblepharon lysis, superficial keratectomy, and AMT onto the bare sclera in the right eye at age 4 and in the left eye at age 8, both under intubated general anesthesia. The other patient underwent the same procedure in the right eye at age 6. Best spectacle-corrected visual acuity improved from ≤20/300 to 20/30 in all eyes, and pupillary zone clarity was maintained during the follow-up period (up to 6 years). Histopathology confirmed pseudopterygium with squamous metaplasia, goblet cell loss, and fibrovascular stroma. Safe general anesthesia was achieved through meticulous multidisciplinary perioperative planning involving anesthesiologists, dermatologists, and pediatricians. No systemic complications related to anesthesia or perioperative management were observed. Conclusions: Single-step OSR with on-lay AMT can restore and preserve visual function in pediatric RDEB. Early surgical intervention may prevent profound amblyopia and provide durable ocular surface stability. A multidisciplinary approach enables safe general anesthesia and perioperative management.
Lemierre's syndrome (LS) is a rare, life-threatening complication of an acute oropharyngeal infection. It is commonly associated with pharyngitis caused by Fusobacterium necrophorum, which can lead to septic thrombophlebitis of the internal jugular vein. Subsequently, septic emboli usually form, which can metastasize to the liver, lungs, endocardium, and joints. The role of anticoagulation in LS remains debated and there is no universal consensus on best practice. A 39-yr-old commercial pilot, flying air cargo operations in Australia, presented to the emergency department with a sore throat, was given antibiotics, and then discharged. He re-presented 2 d later with fever and increased painful swelling of the right lateral neck. A CT scan showed gas-forming thrombophlebitis in the superior sagittal sinus, right transverse sinus, and right internal jugular vein. He was started on broad-spectrum antibiotics and on anticoagulation with enoxaparin. Initial control of the infection was challenging despite antibiotics, requiring a staged surgical exploration and washout of the neck. After reintervention, the patient made an excellent recovery. However, given his anticoagulation, he had to wait several months for clearances from various specialties before the Australian and New Zealand aviation authorities allowed him to fly commercially again. There is currently no consensus in the medical literature on the timing, duration, dosing, or type of anticoagulant for LS, making it challenging to publish unified recommendations for Aviation Medical Examiners. This case report highlights the importance of an individualized approach to prevent unjustified grounding of pilots on anticoagulation. Fandino A, Woodbridge C, Back G, Sprott T. Lemierre's syndrome in a commercial airline pilot. Aerosp Med Hum Perform. 2026; 97(4):296-299.
BACKGROUND: International air border crossings are crucial for controlling the spread of respiratory pandemics like COVID-19. Effective screening at these points is vital for national health security and meeting global health obligations under the revised International Health Regulations (IHR) 2005. This qualitative study aimed to identify and analyze the challenges, barriers, and proposed solutions in COVID-19 screening and management at Iran’s air border crossings and situates these findings within the context of global health governance and pandemic response frameworks. METHODS: Using purposive sampling, twelve key stakeholders involved in border health management were interviewed between Mar and Nov 2024. Data were collected through semi-structured interviews and supplemented by a field visit to Imam Khomeini International Airport’s border health base and a review of relevant international regulations and recent scholarly literature. Content analysis combined with Fishbone root cause analysis was employed to explore underlying factors. RESULTS: Findings revealed multifaceted challenges including inconsistent implementation of screening protocols, shortage of trained personnel, inadequate technological infrastructure, poor interagency coordination, and legal ambiguities related to data privacy and quarantine enforcement. Behavioral factors such as passenger resistance and limited airline cooperation further undermined screening effectiveness. Additionally, the assessment identified significant gaps in meeting global standards and IHR core capacities (points of entry, public health emergency preparedness and surveillance) at air border points. Proposed solutions emphasized integrated digital platforms for real-time data sharing, enhanced staff training, improved quarantine facilities, legal reforms, and targeted multilingual communication campaigns. CONCLUSION: This study indicates that strengthening air border screening during pandemics requires a multisectoral approach aligned with IHR. Identified human, technical, organizational, legal, and environmental challenges may hinder full compliance with these regulations. Addressing these barriers through practical solutions could improve preparedness and response to health emergencies at both national and international levels.
To examine outcomes from respiratory pathogens containment strategies focused on international travellers. We developed a compartmental model generalisable to respiratory infectious diseases, in which international travellers interact with each other and airline/airport workers during transit. We used SARS-CoV-2 Omicron surge data (basic reproduction number (R0): 9.5) as a case example and performed sensitivity and scenario analyses, including varying the R0 for different respiratory pathogens. A US high-volume airport. Simulated international travellers and airline/airport workers. Projection of new and imported SARS-CoV-2 infections without intervention (No Intervention); pre-travel screening for travellers who intend to travel (intended travellers) with PCR (Pre-travel PCR); or antigen testing (Pre-travel Ag); mask-wearing guidance for travellers and workers (Mask-wearing); and a Combined strategy (Pre-travel PCR & Mask-wearing). The number of new and imported respiratory disease infections over the 90-day simulation period. Over the 90-day simulation, the number of infected travellers entering the USA would be: 1 155 580 (27.2% of 4.2 million (M) intended travellers) with No Intervention; 709 560/4.2M (16.7%) with Pre-travel PCR; 862 330/4.2M (20.3%) with Pre-travel Ag; 1033 820/4.2M (24.4%) with Mask-wearing; and 650 480/4.2M (15.3%) with Combined. The number of new infections among airline/airport workers would be: 25 670 (73.3% of 35 000 workers) with No Intervention; 25 260 (72.2%) in Pre-travel PCR; 25 590 (73.1%) in Pre-travel Ag; 24 630 (70.4%) in Mask-wearing; and 18 770 (53.6%) in Combined. In scenario analyses, the most impactful parameters were R0 of the respiratory pathogen and population immunity level. A Combined strategy of pre-travel PCR testing and mask-wearing would most effectively reduce respiratory infection among international travellers and airline/airport workers, but would still allow a substantial number of infections to enter the USA, especially when the pathogen is highly transmissible.
To address multi-distribution perception and temporal generalization challenges in cross-aircraft aero-engine monitoring, the Lyapunov-Schmidt Multi-distributed Perception Network (LSMPNet) is developed as a continuous-time domain generalization framework grounded in improved Lyapunov-Schmidt reduction (LSR). LSMPNet reformulates state monitoring as a continuous nonlinear system, leveraging a T-LSR Decomposer to perform structured decomposition and employing stacked T-LSR Blocks for hierarchical learning of dynamic features. A time-difference-based operator enhances sensitivity to continuous distribution shifts, while complementary manifold topologies strengthen global distribution perception and noise suppression. The linearized operator design ensures low computational complexity and interpretability. Extensive experiments on public benchmarks and real-world cross-aircraft datasets demonstrate superior performance in degradation modeling and water-wash early warning tasks.
At present, commercial air travel rules do not allow people to sit in their own wheelchairs during flight. However, airline seating often does not meet medical needs. In response to current requests to allow this seating option, we researched the crashworthiness and safety of wheelchairs for potential use in aircraft. For motor vehicle travel, many wheelchairs meet voluntary standards for crashworthiness and safety per RESNA WC19. This project assesses whether WC19-compliant wheelchairs can meet FAA aircraft seating standards when secured using 4-point tiedowns. For the FAA horizontal impact testing, computer modeling indicated that a trapezoidal sled pulse was sufficient to represent the more typical triangular pulse, and that due to the flexibility of the tiedown webbing, the effect of the simulated pitch/roll element was minimal. During the initial two horizontal impact tests, fracture of the left front wheelchair caster was observed. The remaining five wheelchairs were tested with an added vehicle-mounted lap belt and were successful at meeting occupant retention and structural integrity requirements. The outcomes show that it may be possible for people to remain seated in a WC19-compliant wheelchair for air travel without a significant decrement in safety.
Work-related shoulder disorders during overhead assembly represent a persistent occupational challenge. We evaluated a quasi-direct-drive (QDD) active upper-limb exoskeleton during simulated overhead work, providing simultaneous metabolic, electromyographic, and kinematic assessment of QDD actuation under static and dynamic conditions. Seven healthy males completed within-subject comparisons of without-exoskeleton (WO) and with-exoskeleton (WE) conditions during dynamic screwing (5 min) and static holding (2.5 min, 3 kg). During static holding, the exoskeleton achieved substantial shoulder offloading (Upper Trapezius: -68.2%, 6/6 participants, p = 0.031, d = 3.61; Anterior Deltoid: -43.6%) and improved postural stability (32-41% variability reduction). However, metabolic cost increased during both static (+57.2%) and dynamic (+30.6%) tasks, while movement smoothness degraded. These findings extend prior task-dependent exoskeleton observations to QDD actuation, revealing that intrinsic backdrivability does not eliminate whole-body energy penalties from device mass. The exoskeleton exhibits task-dependent effectiveness: potentially suitable for prolonged static overhead holding but not currently recommended for dynamic assembly without mass reduction and control refinement.
To address the limitations of weak interpretability and poor generalization in existing taxi-out time prediction models, this study proposes a novel prediction model for departing flights based on Stacking ensemble learning and Shapley additive explanations. Firstly, decomposing taxi-out time into unimpeded taxi-out time and dynamic taxi-out time, followed by separate correlation analysis with influencing factors. Then, constructing a Stacking-based prediction model with comparative evaluation between holistic and phased prediction approaches. Finally, implementing SHAP analysis to quantify feature importance, and validate the rationality of the model using actual operating data from Shenzhen Bao'an international airport of China. The results indicate that: (1) Unimpeded taxi-out time is mainly influenced by the configuration of the airport, while the dynamic taxi-out time is mainly influenced by surface traffic flow; (2) Phased prediction shows enhanced interpretability despite marginally inferior performance (MAPE:12.0%, MAE:113.6s, RMSE:156.7s) compared to holistic prediction; (3) The Stacking model achieves superior accuracy (± 60s/±180s/±300s prediction rates: 41.0%/86.3%/96.5%) and generalization capability over existing methods; (4) The dual feature selection mechanism based on Shapley analysis and correlation analysis can ensure high prediction accuracy of the model while effectively reducing feature dimensions. (5) SHAP analysis was employed to quantify feature impacts on taxi-out time and decode feature interactions, thereby demystifying the model's black-box nature and offering actionable insights for air traffic controllers' decision-making.
Designing an optimal Coverage Path Planning (CPP) framework for autonomous aircraft cabin cleaning is a critical challenge due to the time-sensitive nature of aircraft turnaround operations. Conventional domestic cleaning robots struggle to adapt to the confined and irregular cabin layouts of commercial aircraft. To address this, the paper proposes a two-stage CPP approach utilizing the reconfigurable robot. In the first stage, the robot operates in its full-size configuration to efficiently clean open regions such as aisles and galleys, skipping hard-to-access seat rows to minimize total cleaning time. In the second stage, a Genetic Algorithm (GA)-based Traveling Salesman Problem (TSP) optimization process determines the optimal visiting sequence for the skipped areas, while simultaneously accounting for the robot's reconfiguration energy model. This integrated framework explicitly models the trade-off between coverage efficiency, energy consumption, and reconfiguration cost, ensuring that the robot autonomously selects the most energy-optimal path under operational constraints. The experiments incorporating airline procedures and cabin geometry demonstrate that the proposed approach significantly outperforms conventional CPP strategies in both coverage time and energy usage. The results validate the feasibility of deploying reconfigurable robotic systems for real-world autonomous aircraft cabin cleaning during turnaround operations.
On May 22, 2020, Pakistan International Airlines flight PK-8303 crashed in Karachi, resulting in 97 fatalities. Many victims' remains were burned, fragmented, or commingled, making visual or fingerprint identification impossible. A rapid and reliable Disaster Victim Identification (DVI) process was initiated, integrating advanced forensic genetic techniques with kinship analysis to meet urgent humanitarian, cultural, and legal needs. Biological samples, including bone fragments, teeth, and soft tissue, were collected under strict chain-of-custody procedures. DNA was extracted using optimized protocols for degraded material, quantified via real-time PCR, and profiled with a high-sensitivity autosomal STR multiplex kit (GlobalFiler™). Y-STR and mitochondrial DNA sequencing were employed for cases where nuclear DNA was insufficient. Reference samples from 92 families were analyzed, and kinship likelihood ratios were calculated using dedicated forensic software. Within 16 days, complete identifications were made for 96 victims, with partial matches supporting the remaining case. The combined application of sensitive STR systems, lineage markers, and probabilistic kinship analysis significantly improved recovery rates from compromised remains and reduced turnaround times compared to standard DVI workflows. This case demonstrates how technological advances in forensic genetics can meet the humanitarian imperative of victim identification in mass disasters while ensuring legally robust outcomes.
Jetlag affects millions of travelers daily, yet influences of flight schedules on circadian disruption remain unclear. We aimed to quantify the effects of flight itinerary on jetlag duration at the group-average level and to identify underlying physiological mechanisms. We used biophysical modeling to analyze how flight departure and duration times impacted jetlag across 55 296 simulated flights. Simulated flights spanned time zone differences, ΔT, from -12 to 12 h and departed between 00:30 and 24:00 with durations from 0.5 to 24 h. Two cases were compared: (1) free sleep and (2) forced wakefulness during daytime at the destination. In-flight sleep followed the physiological need for sleep. Flight itineraries affected jetlag duration for all ΔTs and determined the direction of circadian adaptation for a subset of ΔTs depending on behavior at the destination. The highest variability of jetlag duration was observed for ΔT >0 h, peaking at ΔT = 9 h. Overall, for 1 ≤ ΔT ≤ 9 h, jetlag was shortest for flights departing or arriving around habitual wake time and longest when departing or arriving near habitual sleep onset. When in-flight sleep was restricted, the shortest jetlag for these ΔTs was instead observed for flights arriving during the circadian day. This pattern reversed for other ΔTs. Flight departure and arrival times contribute to the variability of jetlag duration and can reverse the direction of circadian adaptation post-flight. These dynamics are mainly governed by light exposure and sleep timing during and around flights. Statement of Significance This study provides a quantitative analysis of how flight itineraries interact with circadian and sleep physiology to determine jetlag duration. By simulating over 55 000 flights across all time zone transitions, we reveal systematic patterns linking flight timing with adaptation time and the opportunities to minimize circadian disruption through itinerary design and behaviors during and around flights. These findings advance the mechanistic understanding of jetlag and offer actionable insights for travelers and airlines to reduce jetlag impact through optimized flight schedules and personalized strategies.