As far as I can tell the only "success" here is making flying affordable for the poorest who used to take Greyhound, and absolutely miserable for everybody, unless you are rich enough to spring for the first class ticket.
Planes are full. What nobody ever seems to address, when talking about seat pitch, is who doesn't get to fly if extra room is added and seats removed?
American, Delta, United, and others all have extra legroom economy seats available for sale for much less than first class. Watch the seat maps on flights, however, and it's always the regular economy (least legroom) seats that fill up first. The majority of passengers do not want to pay for extra space. They'd rather save the money and put up with the cramped seat for a couple of hours.
AAL's is reducing the legroom only in a couple of rows at the back of the 737s. It's not the whole airplane.
Space is already tight in passenger jets and the one thing that really aggravates me is getting stuck next to an obese passenger.
All major airlines have a published procedure for dealing with a COS but they are difficult to proactively enforce if the COS does not take the first steps.
First, there is no simple way to categorize whether or not someone is, or is not, a COS. Every body is shaped differently and most "heavy" passengers are somewhere in the gray area and not clearly in, or out, of the COS category. Even passengers of normal weight and size will spill over the strict confines of their seat at times depending on seating position.
Airline policies generally require, and allow, a COS to buy an extra seat and some offer refunds if the extra seat wouldn't have otherwise been used. Southwest, which doesn't assign seats, allows the COS to pre-board so that they can pick out a two-seat pair and they provide them with a sign, on boarding pass stock, to place on the extra seat to indicate that it is not available to other passengers.
The problem comes in when a COS does not follow these policies and the issue is uncovered on board. While the agents and flight attendants SHOULD be proactive about this, they are put in a difficult situation. It's like asking a women you don't know when she's due and finding out that she isn't pregnant. It's an awkward and embarrassing situation that most people will avoid.
When this situation occurs, it is the COS who should be reseated or removed, not the passenger who is seated next to them. This will likely require that the non-COS passenger bring it up with an F/A and ask for a gate agent to resolve the situation. If the gate agent won't fix it ask for the Complaint Resolution Officer (CRO) who the airlines are required to make available. The CRO is specially trained in the Air Carrier Access Act (the federal regulation which deals with disabilities on airline flights) and will be familiar with the airline's COS policy.