What does it mean when a parakeet flaps its wings really fast?

If you had your parakeet's wings clipped then they are probably growing back now. Your Parakeet might be flapping to see if he or she can fly again yet.

All species of birds occasionally flap their wings around as a form of stretching exercises. So your parakeet may be stretching or exercising, which is good as it helps their lungs, chest and wings develop.