Airlines have warned that a new compensation package for travellers facing delays, cancellations and over-bookings would lead to a jump in ticket prices.
The Europe-wide laws guarantee cash payments of up to €420 for people bumped off flights plus other benefits including meals and drinks during hold-ups.
Tens of thousands of air travellers are expected to gain when the new rules come into force early in 2005.
But budget airline easyJet said the deal could have a "dramatic impact" on the industry and would lead to more expensive fares. The fixed compensation rate for cancelled flights in some cases far exceed the cost of the ticket, a spokeswoman for the carrier said.
She said: "Of course this will put up airfares. If you are on a cancelled €37 flight to Belfast and the airline has to pay you €178, ultimately the cost of the fine is going to pushed on to passengers. Who else is going to pay for it?" The compensation should be a percentage of the ticket price, not a flat rate, she said.
The Air Transport Users Council said the new rules were good news for passengers and would help "concentrate the minds" of airlines.
"The carriers have created this problem themselves," said Mr Simon Evans, chief executive of the passengers' group. "If they hadn't, we wouldn't have needed this legislation." He said airlines have for too long had a "cavalier" attitude to flight bookings and not done enough to honour promises to travellers.
The final deal came after overnight talks in Brussels to thrash out a fair financial package for passengers, coupled with legal obligations on airlines to provide hotel accommodation and meals "where appropriate" when flights are delayed.
Under the new rules airlines which overbook must compensate passengers with cash payments of at least €175 for flights of less than 1,500km, €280 for flights of between 1,300km and 3,500km, and €420 for longer flights.
Hotel accommodation and transport will be paid for by the airline when the revised departure time is at least a day after the original planned take-off.
A Ryanair spokesman said: "If the EU was really serious about eliminating overbookings, they'd just outlaw the practice."
