There is a FAA regulation FAR 121.391 that requires 1 FA for every 50 seats, starting from 20 seat aircraft, up to 19, no FA is required, so an airplane that seats 180 total requires 4 FA’s. Any amount of FA’s over the minimum the airline uses as listed in its emergency evacuation demonstration is then mandatory, so if the airlines uses 7 FA’s, than that is the minimum required under their operating certificate, if they want to add more for better in flight service, they can but they must have at least the minimum for dispatch.

So an AA B-767-200 with it’s 3 class seating seats about 168, then what governs the amount is what is listed on their operating certificate, so AA can add more and they can legally adjust up or down depending on the passenger count and union rules, which I expect is specific to the minimum amount of FA’s that AA is required to have on board a specific model airplane over the FAA requirement

In comparison Spirit Airlines crams 178 passengers into their A-320’s, and all they have is the legal minimum of 4 FA’s on board, because that is what is listed on their operating certificate.

I believe the same goes for boarding, there must be a minimum of FA’s on board before the passengers are allowed to board in case a fire breaks out on board while at the gate to help evacuate the passengers.

Mr. Elliott