So how do airlines really make money? If you think the answer is selling tickets to get you from point A to point B, you’d be wrong.

Airlines made about $110 billion last year from ancillary fees – charging you to check bags, ticket fees or for preferred check-in as the airlines study the maximum amount of money each customer is willing to pay for these services.

Right now, on average, passengers will spend about $24 per flight for these fees. In 2010, we only spent about $8.

Ancillary bills now pay for about half of the airline’s fuel bill, and those fees are only expected to go up this year.