Sometimes, when I'm flying on the airlines, I'll board an aircraft where the aisles seem incredibly cramped, where it's almost impossible to move past without bumping every seat. I can't imagine how much of a nuisance it'd be for people larger than me! I once saw an obese person a bit stuck between one of the aisles, blocking the way for others to move into the aircraft.
But then I thought about what would happen in an emergency. What if there were numerous large people on board, and there was a fire?
So, are there any limits to how much the airlines can squeeze their planes' aisles?