Also if your already flying away because of something (other player pushed you away, etc) you can do various of things.
I personally relax all in the air, because that slows down your speed and you might end up in the floor quickly.
Then there are some basic steps what you need for a comback: a contracted ankle, a contracted knee, contracted writs/elbow, etc.
That basically depends on how you land. Try not to land on your back, or if you do then make sure your opponent in ahead of you, since then you can only use your legs.
Patience is also an important thing. You dont rush the comebacks. If you see that you need more frames then you got, you can jump but thats not exact, wait for it because hat will be better.
Always try to get the best pose you can, and then launch at the enemy. Rest assured.