Hookfly is a flight technique for 2 tees. It uses the hook and is a lot easier with a wall of hookthrough between the 2 tees. Parts usually force you to use hookfly instead of hammerfly by removing the ability to hammer other tees.
Initiating hookfly (with a wall of hookthrough):
Each hook will pull the lower tee significantly higher than the other tee was. Thereby you will gain height each hook and are able to fly upwards indefinitely.
To initiate a hookfly mid-air, one tee has to cancels its fall by doublejumping and hook the other tee up.
Hooking the other tee the moment you are are just barely above him won’t get the other tee very high. Instead, wait a little longer until
Without the wall you will have the problem of bumping into each other, which will break the rhythm.
To counteract the missing wall, steer away from the other tee whenever you are hooking. You must move far enough to not collide, but have to stop before the other tee has to aim its hook in order to not mess up the aiming.
For horizontal flight, the 2 tees will no longer have a side dedicated for each, but will instead revolve around each other.
To hookfly horizontally:
To throw another tee, jump above it and hook the tee upwards and hammer it while it is next to you. You have to dodge the other tee by moving to the side to not have it bump into you.
In a nutshell, hammerhitfly is a very precise chain of 2 tees taking turns to throw the other tee up.
Only the currently hooking tee moves. Move to the side after the start of the hook to dodge the other tee on its way up. Optionally move towards the other tee again if you are out of hammer range.
If you fail the hammering, simply continue the cycle, you should be able to keep the fly up.