Are we talking about the mobile version of PC version here? On mobile devices the precision of the self shadowing ( e.g. the shadows that are casted by the airplane onto itself ) might be a little low on certain mobile devices and depending on your view. For further discussion please provide a good screenshot and a description of your device.
I have a 99% chance that this fact is in the PC version, where some users complain about the shadow of the wings, textures on the plane itself as they show in the topic below where some photo captures are attached.
RE: Options to reduce (Remove) the shadow on airplane textures.
Regards,
Lucas