Passenger fees and other extra charges generated $27.1 billion for airlines around the world in 2012, with major carriers like United, Delta and American airlines leading the revenue race.

In 2012, 53 airlines around the globe collected $27.1 billion in such ancillary revenue, compared with $22.6 billion collected by 50 carriers in 2011, according to a new report by IdeaWorks Co., a Wisconsin consultant on airline fees. The study was sponsored by CarTrawler, a Ireland-based provider of car rental distribution systems.

Extra charges such as baggage fees and charges to upgrade to roomier seats have become a major source of revenue for airlines since 2008, when surging fuel prices forced airlines to find another way to generate money without raising airfares.