How can one perform the prayers (Dhuhr, Asr, Maghrib, and Isha) on an airplane during a long journey extending for hours, with varying times of sunrise and sunset between the points of departure and arrival, which causes confusion in determining prayer times?

It is permissible for a traveler to delay the Dhuhr and Asr prayers and combine them until just before sunset if he will disembark before sunset on the same day of his travel. He must pray according to the prayer times of the country he arrives in, and it is not valid to pray according to the prayer times of the country he departed from. As for returning, if a Muslim travels before the Dhuhr prayer and realizes that sunset will occur while he is on the plane, he must pray Dhuhr and Asr combined before sunset.