Airline economics for dummies

Apparently Concorde needed one ton of fuel per passenger, that's about 2,000 pounds of fuel. A 747 takes one-quarter that amount, so 500 pounds of fuel. I will soon be making a round trip to England by 747 so that will be 1,000 pounds of fuel burned to haul me there and back. Total cost of ticket exluding taxes: $270. By my calculation a thousand pounds of fuel is about 100 gallons so I'm buying 100 gallons of aviation fuel, plus paying for all the rest of the airline infrastructure costs, employee salary, food (okay, thats about $1 worth) etc. etc. Its easy to see how airlines are barely making a profit at this price. I guess I'm just along for a cheap ride with the 1st and Business class people who are paying the bulk of the cost.