Well, I've started traveling more lately. And I've looked at (namebrand) Airlines, 'cos their fares are generally the lowest. And I'm overweight, so I went to their website to get information to see if I would need to buy 2 seats.
Guess what? Even after talking to a real person, I couldn't get a straight-forward answer. Apparently, it is decided by the eye of the gate agent. So, if I only bought 1 ticket, and they decided I needed 2 - if the flight was full, it was 'too bad, so sad' and I would be on the next flight. Which doesn't work when you're traveling with a group, or making connecting flights, or whatever.
I read where this same airline required an overweight person to buy an extra seat, even though she was traveling with a small child, and could have 'overflowed' into that seat with the armrest up. They said it wasn't fair to the youngster.
So, needless to say, I've never tried flying that airline!
whoopi