I don't think this is valid comparison. If you are trying to compare software on a plane to application, then airplane software is not attempted to hack into due to it being generally well isolated from outside networks. If you are comparing physical build of systems in a plane to software, then hacking of software is equivalent to bird or drone running into an engine or a laser attack or hijack attempt... Which while we know do not happen often, but lets say if a lot of money were to be made by doing so, I'm sure the frequency would increase.