Continuity mistake: The Morlocks aren't affected by the light from metal in fusion in their foundry but they recoil from the light of a match.
Continuity mistake: When the men find the tracks of the dinosaur, the indent is flat and rounded, but when Frosty the poodle finds the dinosaur that made the tracks, its feet are skrawny and have pointy claws, which don't show up in the tracks.
Continuity mistake: While Major Allison is piloting the X-80, the style/model of the aircraft differs in shots, and two different numbers appear on its body - FC-226 and FE-229, as well as four different tail numbers that appear on its tailfin - 62216, 70236, 70229, and 61226.
Continuity mistake: When Yosemite Sam sends out robot ZX29B to capture Bugs Bunny, the robot hides by some dustbins by the dump and you can see there are two dustbins by him. When Bugs empties his rubbish into the robot, the two dustbins have disappeared, and when robot ZX29B coughs up the rubbish in the next shot, they are back again.