When John says, "You offend reason sir," Peter floats up. The large light fixture is hanging from the ceiling. However, in the next shot facing Peter when he says, "Just think happy thoughts," where is the light fixture? It's gone so Peter can fly around the ceiling, but it's back again in later shots.
Jeremy Sumpter (Peter Pan) had to go through 6-7 months of flying practice before he could start "flying" in the film.