Under what circumstances of inability to perform salat normally (i.e. while sitting) on the plane, do you have to repeat your prayers when you arrive at your destination (with the intention of qadha)?
You must pray within the time for prayer, even if you cannot fulfill all of the conditions for prayer. So, on the plane, you must try to face the qiblah and pray standing. If, for instance, there is turbulence that does not allow you to get out of your seat, or you are afraid of praying near the bathrooms (where there is a bit of space) because it can cause security issues, then you can pray in your seat. If you can only stand for the takbir, you must do so, and then sit for the remainder of the prayer.