Well, that's really not the answer I was expecting from a developer.
That's the proper answer, considering how lacking of any information your question was. You said passenger have "vanished", without giving ANY details on where you are, which airplane you use, which scenery you use, which kind of parking you use, which kind of jetways (if any) the scenery comes with so, obviously, the only possible reply was showing you that no, nothing has changed and passenger surely haven't gone anywhere.
Provide all the required information, and we might be able to understand why you don't see passengers.