How does a traveler determine prayer times when on a 12-hour flight?

A traveler on an airplane should perform the prayers at their prescribed times. The times for Maghrib, 'Isha, and Fajr can be determined by observation. As for Dhuhr and 'Asr, they can be performed through ijtihad (independent reasoning) and careful investigation. It is permissible for the traveler to combine Dhuhr with 'Asr, and Maghrib with 'Isha. One can seek assistance from the pilot to determine prayer times in the air, or print out prayer schedules for the countries that will be visited or passed through. Whoever strives to know the time, their prayer is valid unless it becomes clear to them that they prayed before the time, in which case they must repeat the prayer.