I've decided to add a "Kiddie Mode":
- Direction keys always move the taxi in that direction, ignoring the orientation of the taxi
- Having the landing gear extended while driving doesn't make you rotate
 

This should make the game more accessible to some players who cannot have fun with it, because they aren't able to get the hang of the relative controls.

They also get their own highscore list:
"Spaß Taxi Kids" ^-^