The pressure on the surface of Mars (0.6 kilopascals or 0.087 psi) is about one tenth of the pressure at the height of 20KM from surface of Earth (Armstrong lim

The pressure on the surface of Mars (0.6 kilopascals or 0.087 psi) is about one tenth of the pressure at the height of 20KM from surface of Earth (Armstrong limit 6.25 kilopascals or 0.906 psi). Of course, the structure of the "Martian" plane has to be designed accordingly. But definitely not impossible though.