From the messageboard:
Here are two frame grabs from ACTIVE STEALTH that show the small store-bought stealth model kit in action. I had the neighbor kid build the model fro $10 and it turned out pretty nice, but it was VERY small -- maybe 12 inches long... You can see Daniel Bladwin running up to it in one shot and the we actually had the balls to try to put a live person in the cockpit! The guy was sitting on the top of a ladder and we lined up the cockpit window with him and he put on his helmet, etc. It was really very well executed. I never would have figured it to work, but it DID!
Total cost maybe $25.
More Forced Perspective how-to can be found here.