Venous thromboembolism (VTE) in legs and lungs is a potentially life-threatening condition. The incidence of VTE associated with air travel is still unknown, but it may have increased. Most travelers who develop symptoms do so within 24 hours after their flight takes off. Predisposing risk factors may be divided into patient-related and cabin-related factors, both of which are described. It is emphasized that better information and better inflight precautions can minimize these risk factors.