How do airlines make money?

Hi all,

This is a question I have wondered about for a while. How does an airline manage to make any money from operations? To start with, you have to buy a multi-million pound aircraft, then fuel it for every flight, employ crew to fly it, engineers to maintain it, pay landing/parking fees, buy spare parts and god knows what else.
It just amazes me that passenger ticket prices don’t have to be higher. Does anyone actually know the sort of profit margins on flights, and what sort of payback airlines have for their aircraft?

Many Thanks,

James