Consumers will pay $58 billion (€41 billion) in so-called "ancillary charges" this year, according to predictions from an airline industry analyst released last week.

New fees on everything from checking baggage to paying for seat allocations are now the industry norm, and although they will make up around only 12 percent of airline revenues this year, they are expected to grow, says the Center for Asia Pacific Aviation (CAPA).

Airline insiders call the fees "ancillary charges" as they are in addition to the standard price of a ticket, prompting complaints from consumer rights advocates. Ryanair, one of the first airlines to introduce such fees, was recently described as "puerile" and "almost childish" by the UK's Office of Fair Trading.

Nevertheless, the trend seems set to continue. Because of the fall in ticket prices since the start of the recession, airlines are desperate for ways to recoup lost revenue and growing ever bolder in ways to do it. In January 2010, four major US airlines - Delta, Continental, United and American - all announced a $25 (€17.82) fee for any checked baggage on internal flights. Although European flag carriers such as Air France, Lufthansa and BA have yet to follow suit, budget airlines such as Easyjet and Ryanair have been charging bag fees for some time. In Asia Pacific also, carriers have "only dabbled" in adding ancillary charges, says CAPA.

Other methods of fee collection such as assigning seats, flying pets or rebooking fees are also set to jump and have experienced considerable growth in 2009, according to the research. For airlines, there seem to be rich pickings ahead - consumers, it seems, will have to get used to extra fees on top of their tickets.

Guide to Airline Fees: