Headline air fares are set to rise after 12 airlines - including Ryanair and easyJet - agreed to scrap fees for paying by debit card. Under a deal with the Office of Fair Trading announced today, the carriers will incorporate debit card surcharges into their advertised ticket prices, rather than adding them at the end of online booking. Budget airlines will almost certainly push up their ‘headline’, or advertised fare to make up the lost revenue. They will still be able to impose surcharges for credit cards, which are more costly to process, but have promised the OFT they will make those fees more transparent. Aer Lingus, BMI Baby, Eastern Airways, easyJet, Flybe, German Wings, Jet2, Lufthansa, Ryanair, Thomas Cook, Thomson and Wizz Air have agreed to the deal. The Office of Fair Trading had been investigating the fees since March when the consumer group Which? made a super-complaint about them. Eight of the airlines - Eastern Airways, easyJet, Flybe, German Wings, Lufthansa, Thomas Cook, Thomson and Wizz Air - have already made changes to their pricing and websites. The others will change their advertising practices by August 1 and complete the changes over coming months. The airlines were under pressure not just from the OFT, but also the Government, which last Christmas promised to ban excessive surcharges for debit and credit charges by travel companies by the end of the year. Customers should not have to face surprise fees for using a debit card, which was the "online equivalent of cash", the OFT said. Clive Maxwell, its chief executive, said: "It is important that the cost presented when they search for a flight is realistic and that they are not surprised by extra charges." He added: "We made it clear from the start that we would use all of our enforcement powers, including court action if necessary, but are pleased to have reached agreement with the airlines before court proceedings were required." The fees can present a substantial hidden extra just before a payment is processed on airline websites: Ryanair currently charges a £6 ‘administration fee’ for debit cards, adding £48 to a holiday for a family of four. Sarah Brooks, director of financial services at Consumer Focus welcomed the news. “Nothing is more frustrating for consumers than seeing a good online deal disappear on the final screen before booking,” she said. Which?’s chief executive Peter Vicary-Smith said: “Over 50,000 people supported our campaign to end rip off surcharges so it's good news that debit card surcharges will be displayed in the headline price of flights - as long as the airlines don't use this as an excuse to push up their prices. “It's also important that credit card charges are clearly displayed throughout the booking process and the OFT should make sure that all companies are taking these steps, not just airlines.”