Actually, the forward/rearward facing argument has more to do with the design of the airplane seats than the desire of the passenger in front to recline.

In the unlikely event of a crash, almost all coach seats are designed to fold forward. If an infant were in a rearward facing seat, they could possibly be injured/crushed when the inertia from the person BEHIND them leaned forward during a "severe de-acceleration". Even if your babe is too small to be forward facing in an auto, they should face forward in an aircraft, assuming they have a 5 point harness. The rigidity of the car seat shell will protect them more from the weight/inertia of the adult behind them than their own forces during the crash. If the babe is so small (think up to about 3 months) and have no body parts (face/hands/feet) extending beyond the hard shell of the car seat they can safely face rearward.

In my opinion (as a mechanical engineer with a 2, 4, and 6 year old), the car seat on the plane is mainly to protect them from turbulence, and to avoid sitting on mommy's/daddy's lap for hours on end. The physics of a SURVIVABLE airplane crash are very different than those in a car.

AA will ask the car seat sit in a window seat, so as not to impede the evacuation of other passengers. It is not supposed to be used in a center seat (the E seat in the AB-CEG-HJ config), but often it would be too difficult to re-assign passengers in this case, so the FA's let it slide.

Hope this helps!