Originally Posted by
pilotalan
Indirectly.
FAA has a max ratio of pax to Flight Attendants. On some planes, with some configurations, you will have a small number of seats that if they book, they have to add another FA.
Have to disagree with you. Since we're talking about a regular commercial flight then it's the seating capacity, not actual passenger count that determine how many F/A's are required. See 14 CFR 121.391(a)
Only when an A/C is operating under Part 91 (CFR 91.533) then it would be based on the number of passengers.