Airlines are expected to collect more than £16.2 billion in ancillary revenues this year, including fees for checked baggage, an increase of nearly £6.5 billion on 2009.

The findings were revealed in a new study by travel technology provider Amadeus, and the US consultancy firm IdeaWorks.  It also predicts that the figure could quadruple to £65.9 billion.

The study found that low-cost carriers – including Flybe, Ryanair, Spirit Air and Tiger Airways – now generate more than 20 percent of their total revenue from ancillary charges.

It also highlighted that the legacy carriers, such as British Airways and Qantas, are also following the lead of low-cost carriers by raising ancillary charges, and bringing in charges for seat selection.

Jay Sorensen, president of IdeaWorks, said: “Airlines worldwide are embracing a la carte fees, and by every measure, the ancillary revenue movement is gaining strength.”

He predicted that baggage fees were likely to increase, and free meals in economy class cabins could disappear entirely.

Only this week easyJet hiked its infant fee from £15 to £20, its booking fee from £3.95 to £4.95, and raised its charges for cancelling or making changes to a booking.

James Fremantle, a spokesman for the Air Transport Users Council, told The Telegraph that the predicted increases should be a cause for concern.

“Although we have no problem with charging for optional services, there’s obviously a limit to how far it can go. You could argue that it benefits some travellers, but it is bad news for families.”

He also urged airlines to improve the transparency of their pricing, and said that all non-optional charges should be included in the headline fare.

Article 23 of the European Commission’s Air Services Regulation, states that “the final price to be paid shall at all times be indicated” and should include all taxes and charges “which are unavoidable”. However, there is currently no UK legislation to enforce this regulation.

A spokesperson for the Department for Transport said: “We consulted earlier this year on proposals which would give the Civil Aviation Authority and Office of Fair Trading enforcement powers for this regulation, and introduce penalties for non-compliance. We expect to make an announcement on this in the near future”.