JeanJohn, even if a friend of yours still might have the app, rest assured it is not going to work as intended. It might find flights (as do so many other apps from travel agents and price comparison sites), but it won't be able to show the fare details. (something no other app did).
So no reason to cry about it for too long.
And as for Apple and Google, yes they can remove any app from your phone if they wish. If you don't want that, in case of an Android-based system you need to load an independent operating system. (in the case of an iPhone, you won't have a choice)