Re: Alien UFOs
> A blimp doesn't look like a helicopter, or the ubiquitous Cessna.
That might be true, but I somehow doubt a mission to some faraway star system would bother lugging those along! Maybe the helicopter (or rather a small drone), but that's all. Payload is at a premium, so you won't bring anything you don't absolutely need. Definitely not a dozen wildly different vehicles just to confuse the locals...
Besides, the F117 might be a little angular, but it's still a central body with wings on both sides, totally plane-like, even the Northrop B-2 "flying wing" bomber is just a central body with (huge) wings on each side: For an alien having no preconception about what a plane should look like, they must all follow the same schema, besides they also all fly the same way (horizontally, wings level, in the direction of the central body).
I agree balloons (helium or hot air) would be different, but then again those are very low-tech devices any halfway civilized alien would probably recognize.