EasyJet and Ryanair are among 12 budget airlines that will no longer add last-minute fees on customers paying by debit card, the consumer watchdog has revealed.
Debit card surcharges will be added in the headline ticket price rather than surprise consumers at the end of the booking process, the Office of Fair Trading (OFT) said.
Surcharges for credit cards are also going to be clearer and easier to find during the booking process, the OFT added.
Aer Lingus, BMI Baby, Eastern Airways, easyJet, Flybe, German Wings, Jet2, Lufthansa, Ryanair, Thomas Cook, Thomson (TUI) and Wizz Air were subject to an OFT consumer law investigation and have agreed to change their practices.
Clive Maxwell, the OFT's 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."
The government has also announced plans to bring forward legislation to ban excessive debit and credit card surcharges, which cost consumers £300 million a year from the airline sector.
The OFT said people should not have to incur surcharges to use a debit card online as they are the "online equivalent of cash" which means that headline prices should be the price people can pay.
However, the OFT said traders may still impose surcharges for credit cards, which can be more costly to process.
Eastern Airways, easyJet, Flybe, German Wings, Lufthansa, Thomas Cook, Thomson (TUI) and Wizz Air have already made changes to their pricing structures, websites and marketing materials.
Other airlines will change their advertising practices by August 1 and fully complete further changes over the coming months.
Mr Maxwell continued: "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 watchdog launched a 90-day investigation in March after a super-complaint from independent consumer body Which? highlighted consumer anger about the increasingly widespread use of surcharges.