You are not 6'5, so you do not need extra space on a plane. I don't care if you are tired and want to sleep. I, and many other people on the plane, fell asleep just fine with our seats in the upright position. Also, if the person behind you is pushing on your seat, that is a sign you are crowding them. Sitting up and then leaning back to where you were does not solve the problem.

No love,
The guy behind you for 4 hours