Reference: Fataawa Mu’aasirah – Page 25;
Majallah ad-Da’wah No.1757 – Page 45
Question: A man travelling by plane does not know the direction of the qiblah, because no-one [on the plane] knew the direction [of the qiblah]. He therefore prayed, but did not know whether or not it was in the direction of the qiblah. So is the prayer in such circumstances correct?
Response: A passenger on a plane wanting to pray a voluntary prayer can do so in the direction his seat is facing, and he is not required to face the direction of the qiblah. That is because it has been confirmed that the Prophet (sal-Allaahu ‘alayhi wa sallam) would pray upon his riding beast in whichever direction it was faced, when he was travelling.
As for the obligatory [prayer], then it is imperative to face the qiblah, [just as] it is imperative to do the rukoo’ and the sujood if possible. And based upon that, whoever is able to do that in a plane, then should pray in the plane, even if the current prayer is from that which can be combined with the one after it. For example if the current prayer is the Zhuhr prayer, then he can delay it so that he can combine it with the ‘Asr, or if it was the Maghrib [prayer], then he can delay it so he can combine it with the ‘Ishaa [prayer].
And it is obligatory upon him to ask [any of] the cabin crew about the direction of the qiblah , if there isn’t a qiblah sign in the aircraft. And if he does not do that, then his prayer is invalid.