MaxJet and Eos, the two business class-only airlines launched with last October are already struggling with load factors of less than 35 per cent, according to reports.

According to figures from the Civil Aviation Authority, the two airlines, which both fly daily between New York’s JFK and London’s Stansted airports, filled just 2,563 of the combined total of 8,484 seats on offer in January.

This represents a load factor of just 32 per cent, well below the level consistent with breaking even. Earlier this month British Airways reported a load factor of 71.2 per cent in February.

A spokeswoman for Eos, which has a small fleet of Boeing 757s fitted with just 48 fully reclining seats, denied that Eos was in any financial difficulty.

"Our numbers are healthy and improving all the time," she said. "We are adding a second service on the same route in a couple of months' time, which shows there is the demand for the service.

"Eos has a substantial amount of funding from private equity so we are in a stronger position than our main rival."

The spokeswoman said Eos had raised start-up capital of $185 million (£110m) from a number of high-profile American private equity firms including Golden Gate capital and Sutter Hill ventures.

Gary Rogliano, the chief executive of MaxJet, denied that his airline was struggling. "We are backed by a number of ultra-high net worth individuals who are determined to make a success of the business," he said.

"January was a very low period –travel drops off about 30 per cent from December - we knew we had to weather that storm as does everyone in the industry. But we are very pleased with our load factors in March, which have picked up significantly. And our forward bookings for April, May and June are double what we had earlier in the year."

Mr Rogliano went on to attack Eos. "They are the airline that has been carrying just five or ten passengers per flight. Even they know their business model is not working and that is why they are trying to change their strategy.

"We are not even in competition with them. We are a value proposition and are targeting people who want to travel in comfort but do not want to pay thousands of pounds to cross the Atlantic."

Eos charges £3,500 for a return flight but the company is also offering "leisure" fares at £950 each way.

MaxJet charges a more modest £854 but it carries 102 people in each plane. Both airlines offer gourmet meals, fine wines and a high ratio of cabin crew to passengers.

In an interview with The Guardian, David Spurlock, the former strategy director at BA who runs Eos, said he was very pleased with how things were going.

"What stands out most strongly is the absolutely incredible feedback we're getting from everybody who touches or flies Eos," he said.

Transport analysts are sceptical about whether the two airlines have sustainable business models. Other leading airlines with bigger fleets, more destinations and more flights can offer greater flexibility and cheaper bulk deals to corporate clients.

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