While travelling in the flight, due to tight schedule and unavailability of space and water for Salaat, we make Salaat in our seats without wudhu.

Answer

It is possible to make wudhu in the plane. We have travelled a hundred times in various planes. Never once was there a need to perform Salaat without wudhu. You have to make wudhu in the plane. The Salaat which you perform with wudhu in the seat, should be repeated on landing. Performing without wudhu is unacceptable.