Airlines collected $31.5 billion in 2013 by selling more than just seats on planes, according to new data analyzed by CarTrawler, a rental car services company, and IdeaWorksCompany, which helps airlines build these non-traditional revenue streams.
The money was made by collecting fees and charging for various programs.
For a typical U.S. airline, about 25 percent of the revenue comes from baggage fees and 10 percent comes from other a la carte services, such as early boarding and the sales of soft drinks. About 5 percent comes from package deals, such as hotels, rental cars and insurance programs. The largest share -- 60 percent of such revenue -- comes from selling frequent-flier program miles to credit card companies and others.
For low-cost carriers like Spirit Airlines and Allegiant, fees are a high percentage of their total revenue. Spirit Airlines ranked first with the highest percentage of revenue from fees -- 38.4 percent of its total revenue in 2013.
Take a look a which airlines collected the most in fees and programs in 2013.
10. US Airways. Total ancillary revenue: $1.1 billion
9. Quantas Airways. Total ancillary revenue: $1.27 billion
8. Lufthansa Group. Total ancillary revenue: $1.28 billion
7. easyJet. Total ancillary revenue: $1.38 billion
6. Southwest Airlines. Total ancillary revenue: $1.62 billion
5. Ryanair. Total ancillary revenue: $1.68 billion
4. Air France/KLM. Total ancillary revenue: $1.7 billion
3. American Airlines. Total ancillary revenue: $2 billion
2. Delta Air Lines. Total ancillary revenue: $2.52 billion
1. United Airlines. United Airlines collected more than $5.7 billion in ancillary revenue last year, more than any other airline analyzed in a new report.
Jet2.com made the most money per passenger, collecting $55.61 each, followed by Spirit's $51.22 per passenger.
Click here to read about the most satisfying airlines.