When George dreamed, he knew how to fly. When he woke up, the secret knowledge would slip away, lost in the fog of morning. For as long as he could remember, George had been tantalized by vivid dreams of flying. Not in a plane, or rocketing through the air. The flights he dreamt were more like floating. The lazy, aimless drifting of a balloon. Nowhere to go. No rush to get there. The dreams came to him sparsely, two or three times a year. Some years, not at all. They were quite consistent. First, a sense of letting go, of allowing, giving consent for gravity to release him. Then—moving his arms up and down—slowly, in a gentle undulating motion, like a swimming stroke, starting at the shoulders and easing down to the hips. Repeating the motion would lift him gently up into the air.

Thanks,
Dave Bowen

From your first three sentences I'd say you might need a comma-ectomy. Only the comma after 'slip away' seems truly necessary.

I'd also add, "'But' they were quite consistent."

There's no real hook in this thirteen except the promise that it's SF. I hope you get to the speculative element fairly quickly.