Originally Posted by Dr. HFH

There's some inherent ambiguity in the way that we describe airline seats. A seat can recline to perfectly flat, yet still be a few degrees off horizontal to the floor. A "165° recline" could mean that the seat reclines flat but at a 15° angle to the floor. Remember, too, that larger, long haul aircraft typically cruise at an incline of 3-4°. So if the seat reclines flat and is parallel with the floor, your feet are still slightly above your head.