In the "Balloonatics" segment, when Rabbit tells Pooh, Piglet, and Tigger to raise their right hands and right legs, Pooh does so like the others. But in the next shot, when they're jumping up and down, Pooh has his left hand and leg raised.
Christopher Robin uses his breath to re-inflate the balloon, and it floats. Only helium makes balloons float, as people only breathe out Carbon dioxide, ergo breathed-inflated balloons do not float.