When Ed Thompson, a photographer, and his partner Rosaline Fraser Brown, below, turned up at Gatwick airport in June for their easyJet flight to Thessaloniki they were told that the aircraft was full and they would have to spend the first night of their holiday in an airport hotel. Not only was their sunny Greek trip cut short, they are still, two months later, waiting for €800 (£571) in compensation.

The couple are representative of thousands of travellers who, despite having booked months in advance, are being caught out by the common policy of overbooking flights. Many complain that though airlines are legally obliged to compensate “bumped” passengers immediately, they are failing to do so promptly, or in some cases, at all.

Michael Holden’s 18-year-old daughter, Jasmine, and a friend had a similar experience with easyJet in mid-July. Trying to check in online the night before their flight from Luton to Palma, Majorca, she was told there was a “system fault”. They checked in at the airport, went through security but when they got to the boarding gate were told there were no seats and they had to wait eight hours for the next flight. They arrived at Palma airport late that evening, their pre-arranged and paid-for transfer having long since gone. Mr Holden says: “I thought it was outrageous that easyJet considered it acceptable to dump two 18-year-old girls at midnight at a Spanish airport without any assistance.”

Miss Holden has since been trying to claim her compensation, and has this week been told it will take another 15 to 20 days to land in her account.

Until Times Money contacted Air Berlin, reader Dave Hebden, who was separated from his wife and daughter on an overbooked Air Berlin flight to Salzburg via Hamburg, had been offered only vouchers towards a future flight by way of compensation, though he had to fork out €180 (£130) for a taxi as a result of missing his original flight.

A spokesman for Air Berlin says it regrets any inconvenience caused.

He says: “It is a major concern of Air Berlin to offer our passengers reliable and comfortable transportation. For courtesy reasons we will refund the amount of €250.”

Both scheduled and low-cost airlines frequently overbook flights, says Bob Atkinson of website TravelSupermarket. Charter airlines such as Thomson and Thomas Cook do not because package-holiday tourists are unlikely to miss their flights.

“Airlines know from historical records which flights attract bookings and have no-shows, meaning empty seats. Flights to business destinations are particularly prone to this, where businessmen have flexible plans, will buy multiple tickets and cancel what they don’t need last minute or change their ticket for a fee at short notice. This results in empty seats which don’t make revenue. Hence airlines will overbook.”

EasyJet, the worst airline for complaints about overbooking according to Resolver, the complaints handling website, says that 2.6 million of its passengers a year do not arrive for their flights.

A spokeswoman for easyJet explains that its flights are overbooked only after reviewing the no-show rate for the past three months, and on average will overbook by one or two passengers a flight. “As a result it is extremely rare for easyJet to deny boarding of passengers.”

The airline has agreed to refund Mr Thompson and Ms Fraser Brown who, it admits, should already have received compensation of €400 each.

James Walker, of Resolver, says: “Before an airline bumps passengers off a flight, they will look at who they can upgrade to a premier cabin, so be dressed to impress and you are more likely to be upgraded. Often airlines will offer volunteers above and beyond the minimum compensation, so it is worth considering this if you don’t actually mind being bumped off the flight.”

If there are no volunteers airlines can start denying boarding to other passengers. When this happens you are entitled under EU law to the same level of compensation as if you were on a delayed flight. This applies only to flights to or from a European airport, or on a flight on an EU airline.

According to the Civil Aviation Authority the airline must refund your ticket price within seven days or provide an alternative flight plus a sum based on how long you have to wait for the new flight. This applies even if the calculation is only theoretical because you opt for a refund. The sum varies from €125 for a delay of less than two hours on a short haul flight under 1,500km, to €600 for a delay of more than four hours for a flight over 3,500km.

A spokesman for the CAA says: “The airline should provide you with meals and drinks, and hotel accommodation where appropriate. You may prefer to return home if it is possible to do so and return for your later flight.”

Travel checklist

  • Check in as early as you can online and print your boarding pass, this registers your intention to fly, says Mr Atkinson
  • Ensure you arrive at the airport on time, as if you are late you are more likely to be denied boarding
  • Board early rather than rushing to the gate at the last minute
  • If you fly regularly join a frequent flyer scheme and collect points on all flights you can. Loyal customers are less likely to be bumped