Yeah it was a very tight deadline, so its hard to get everything fixed of course. It wasnt really a problem once I figured it out though, so hopefully other players dont get stuck on it :)
Regarding the exploit: If you have a booster selected when the flying starts, then you can build->remove->build->remove->build the booster infinitely during the flying phase, and it just restocks your fuel.
There is nothing that prevents you from building when its flying :D