When you try to fly a plane like the Ju-87, it says you need 2 crew member but, in order to get another crew member you need to be able to fly. So its impossible to fly the plane because you need 2 people but, there is no way of unlocking another one because the upgrade requires flying. I’m pretty ticked about that.
You can actually get pilot from any box for crew you get. Thats how I got mine.