What about getting an indoor plane? I know you said you had no interest in electrics, but what about something like a Park Zone Ember or Vapor? If you wanted something more advanced maybe the Sukhoi. These would small enough to store practically anywhere. On my campus there are plenty of large lecture halls that aren't used at various times in the day. And I even saw a guy flying a foamie profile in the rec center gym once when it wasn't busy. So that could be an option.

It may not be ideal, but would let you get your flying fix until you can come up with something better.