Supplementary charges for hold baggage, allocated seating and checking-in have risen greatly in the past year, according to comparison site Travelsupermarket.com.
Extra charges can make up 65% of the total ticket price, according to a study by the company.
Almost all of the 12 airlines surveyed had increased charges to check-in bags, with Thomson now charging £22 each way on a short-haul route to check in a 20kg bag, up from £15 last year.
Monarch passengers who need to check in an additional bag at the airport will be charged £50 this April, up from £30 last year.
Ryanair has increased the charge for reissuing a boarding pass at the airport from £60 to £70, while taking an infant along on a flight will now cost £30, up from £20.
Bob Atkinson, from Travelsupermarket, said: “In recent years there has been a blurring of how low-cost, holiday airlines and traditional full-service airlines operate.
“In some instances, opting for a full-service airline such as British Airways or Lufthansa can work out cheaper than an airline with itemised extras.”