I dreamed several times that I waved my arms and floated into the air, but I could still control the height. Is there a reason?

Generally speaking, there are several situations in which you dream of flying or floating:

I've been in a good mood recently, and my fortune is good.

Spinal nerve is excited.

Eating certain things or drugs can stimulate the excitement of the body.

Influenced by the outside world, such as watching some similar movies before going to bed, or having such fantasies, etc.

Combine your own situation, analyze yourself and see if there are any of the above.