There are 3 continuity errors when Billy takes a ride with Alan Shepard:
1. The plane on the tarmac has a different tail number than the plane in flight.
2. The plane on the tarmac has no name under the rear seat's canopy but the plane in flight does.
3. When Billy makes a left turn the exterior shot is flopped to make the plane's right turn appear to be a left turn (the tail number is mirrored).
Although set in Cocoa Beach, Florida, Billy's jet ride with Alan Shepard lands at what is clearly Edwards Air Force base in California. There are no mountains in Florida, yet the air strip background clearly shows a Mojave mountain range.