Airlines that boast about low prices can be more expensive than their rivals when extra costs are added to headline fares, according to a new study.

British Airways was cheaper than Ryanair and Wizz Air on two out of three routes analysed, according to consumer group Which?

Researchers conducted a snapshot price analysis for the cheapest return flights from London airports to Malaga, Athens and Naples with Ryanair, Wizz Air, British Airways, Jet2 and easyJet booked in December 2023 for travel on weekends this month.

They included the price of taking a cabin bag as hand luggage.

The cost of seat selection was added for Ryanair and Wizz Air as a previous survey indicated they are the airlines least likely to automatically seat travel companions together.

The study found that while budget airlines often had the cheapest headline fares, Ryanair and Wizz Air failed to return the lowest price on any occasion when the cost of a cabin bag and seat selection – always included in British Airways and Jet2 fares – were taken into account.

British Airways was found to have the lowest total price for Naples flights, at £120.

That compares with £198 with Jet2, £185 with Wizz Air, £132 with Ryanair and £126 with easyJet.

British Airways was the second cheapest airline, behind easyJet, for Malaga flights, but the most expensive for trips to Athens.

Baggage and seat selection accounted for an average of £113 across the three routes with Wizz Air, £57 with Ryanair and £52 with easyJet.

Wizz Air’s cabin bag fee includes priority boarding.

Unavoidable hidden charges for online consumers – or “drip pricing” – is to be banned under the Digital Markets, Competition and Consumers Bill progressing through Parliament.

Optional extras are not included in the legislation, but Which? believes fees for seat selection on flights should be covered.

Rory Boland, editor of magazine Which? Travel, said: “It’s easy to assume that budget airlines like Ryanair and Wizz Air are always the cheapest option.

“But if you want to sit next to your kids or take more than a few items of clothes with you, then you’ll increasingly find better prices elsewhere.

“Next time you’re booking a flight, look beyond the headline fare and factor in the cost of extras you need, before you book.”

A Ryanair spokesman said: “This is more fake news from Which?.

“Ryanair has the lowest fares of any airline in Europe and additional ancillary products, such as extra luggage, are entirely optional for customers.”

A spokeswoman for Wizz Air said its “average price” for cabin baggage and priority boarding is “much lower” than the one found by Which?

She went on: “As an ultra-low-cost carrier, we allow passengers to choose which services they wish to purchase so that we can offer the most affordable travel opportunities.

“Optional add-ons are not required to fly, and we believe that customers should be offered the choice and flexibility to choose the right products for them.”