So, I had a level 5 base in Venice, that I just upgraded, and after I filled the slots (just tinkered with routes that were already there) the whole base disappeared... I have had the base for over a week, but now, no money, no planes, no base... Pretty much sunk my airline. lol.
Not sure why the glitch happened, but it did. As I said, just happened after I adjusted slots on routes I already had.