EasyJet stuck to a five-year-old pledge yesterday and promised not to introduce a fuel surcharge, even as its shares fell 17 per cent amid warnings that it would be spending £45 million more than it had forecast on aviation fuel in the second half of the year.

A profit warning from the low-cost airline dragged down the aviation sector and easyJet predicted worse to come from its rivals, which it said were basing their forecasts on oil at $850 a tonne, while it had risen to more than $1,000 a tonne.

At one point, shares in easyJet fell to 310p, but they recovered to close down 9.6 per cent at 336p.

Andy Harrison, the company's chief executive, told investors that a sustained period of $110-a-barrel oil, which had forced aviation fuel prices up, had put paid to the company's hoped-for 20 per cent increase in profits.

Analysts altered their profit forecast from about £230 million to £185 million for the full year as the company made clear that it would be unable to pass on any of the £45 million higher costs to passengers.

Mr Harrison also suggested that rival airlines, including British Airways and Ryanair, would have to reassess their exposure to the rising oil price because warnings from the two had been made before the latest prolonged increase in oil prices. He speculated that some of Europe's more vulnerable airlines would go to the wall, finally appearing to concur with Ryanair's prediction of a looming “perfect storm” in aviation. “If oil continues at this price, some of the weaker players will disappear,” he said, although he refused to name which airlines he believed were most threatened. “Whatever happens, the fundamental economics of easyJet are still strong,” he added. “There are only two short-haul airlines in Europe that make money and easyJet is going to be a winner in the medium term.”

The profit warning highlighted that first-half results were likely to be in line with expectations, with February load factors 1.8 per cent higher than in the same month the previous year.

Easter trading was on track, the airline said, and 27 per cent of summer seats had been sold, slightly ahead of last year. “This is not about economics or consumer spending, it's just oil prices,” Mr Harrison said.

EasyJet's warning came after an update only seven weeks ago when the airline repeated its guidance of a 20 per cent improvement in profits.

Only days earlier Ryanair, Europe's most profitable airline, said that rising fuel costs, deteriorating consumer confidence and the weak pound would put severe pressure on costs. The airline said that profits for its next financial year could fall by as much as 50 per cent.

EasyJet had argued that, unlike Ryanair, it had some immunity from a soaring oil price because it had hedged 40 per cent of its fuel for this summer at $750 per tonne.

Analysts are uncertain how low-cost airlines will fare during a prolonged economic downturn. It is unclear whether they will suffer as consumers cut back on discretionary travel or benefit as travellers trade down from full-service airlines.

Shares in easyJet have fallen by almost half since the turn of the year.

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