Corrected entry: In the scene where Homer and Bart are gonna blow up the dome they are riding on the bike round the dome. When Bart apologizes to Homer they look like they're floating in mid air rather than driving round the edge of the dome.
MasterOfAll
17th Aug 2010
Correction: The shot is a closeup of them and they are moving at high speeds on a clear dome. It can appear that they are floating but they are still on the dome.
MasterOfAll