How to Pray in an Airplane
Question :
I had an important duty and the time came for prayer while I was on board an airplane, so I prayed while I was sitting in the seat of the plane, bowing my head, without knowing which direction I was facing. I request you to inform me if my prayer was correct, and if it was not correct, should I have delayed it until after I got off the plane?
Answer:
It is an obligation upon the Muslim when he is onboard an airplane or in the desert to try his best to ascertain the direction of the Qiblah, by asking the people who know, or by looking for signs which will reveal the direction of the Qiblah, so that he may knowingly pray towards the Qiblah.
If it is not easy for him to find this out, he must estimate and strive to find the direction of the Qiblah to the best of his ability and pray towards it, and it will be sufficient for him, even if it becomes apparent later that he was mistaken in his estimation of the direction of the Qiblah, because he exercised his judgement and feared Allah as much as he was able.
It is not permissible to perform an obligatory prayer on an airplane or in the desert, without striving and exercising one's judgement (to find the Qiblah), and anyone who did so would be obliged to repeat the prayer, because he had not feared Allah as much as he could and striven to the best of his ability. As for the questioner having prayed sitting, there is no objection to this, if he was unable to pray standing, like the worshipper in a ship or a boat, when it is not possible for him to stand. The evidence for this is the Words of Allah, the Most High:
So keep your duty to Allah and fear him as much as you can.
If he delayed the prayer until he left the airplane, there would be no objection to this, so long as the time permitted it. All of this is regarding the obligatory prayers; as for the supererogatory prayers, it is not necessary to face the Qiblah therein when one is in a plane or car or on a riding beast, because it has been authentically reported from the Messenger that he used to pray the non-obligatory prayers while he was on his camel in whichever direction he was travelling. However, it is preferred for him to face the Qiblah at the start of the prayer, then complete the prayer in whichever direction he is travelling, because proof of that has been authentically reported in the Hadith of Anas, may Allah be pleased with him. And through Allah is attained success.
Source:
Ibn Baz
Fatawa Islamiyah, Vol. 2 Pages 171-173-173