It is not always easy to determine the time for any salat on the plane. Please advise on how this should be done, particularly when traveling long distances.
Concerning the times for prayer, you do not have to pray at the earliest time. And it is generally possible to determine the times either because the sky is turning bright again or because it is turning dark, or the sun has crossed the midpoint in the sky and is descending. And if you can’t open your own shade, you can still open the ones by the bathrooms.