Currently, under EU261 rules, passengers on a domestic flight in the UK can claim £220 once their flight has been delayed by three hours.

The government announced in January it was considering scrapping the current framework and offer compensation based on ticket price and the length of delay instead – similar to the Delay Repay system used in rail. 

A Department for Transport (DfT) consultation on the subject ends on 27 March.

However Which? claims the proposed new system would see compensation “plummet” to just over a quarter of the current amount as the average sum eligible to each passenger dropped from £220 to £57.  

Using figures provided by Skyscanner, Which? calculated the amount carriers would have to pay for long delays on some of the most popular UK routes.

When flying at a full capacity of 180 passengers, and if everyone eligible was to be compensated, an airline’s typical £39,600 payout for an Edinburgh to London delay of three hours or more would shrink to £7,920, Which? claims, while Gatwick to Belfast could go from £39,600 for delays to £9,900.

While a lower level of compensation could become available to more people, Which? said it believed it would be “wrong” to switch the system.

“Passengers can face missing out on a holiday, with ongoing travel and accommodation costs, if they are affected by severe delays or cancellations once they have reached the airport terminal, so in many cases it is potentially far more costly than missing a train,” said Which?.

The changes would also “disproportionately affect” people living in the devolved nations and regions of the UK more likely to take domestic flights.

Which? said it was concerned the UK plan could set a precedent and weaken passenger compensation rights throughout Europe.

It is calling on the government to reconsider proposals and instead increase enforcement around compensation, adding how it supported proposals in the same DfT consultation to grant administrative fining powers to the Civil Aviation Authority (CAA) and make it mandatory for airlines to join the Alternative Disputes Resolution (ADR) scheme. 

Which? Travel editor Rory Boland said: “The government should reconsider these reforms and instead give passengers confidence that they will be protected when their journey is disrupted by giving the aviation regulator the powers it needs to crack down on airlines trying to flout the rules.”