Mumbai: Virgin Atlantic owner Sir Richard Branson has sought the support of US presidential candidates Barack Obama and John McCain for blocking a proposed link-up of American Airlines with it two main European partners - British Airways and Iberia.

The three airlines are expected to seek US government permission for closer cooperation on the trans-Atlantic flights as they try to cop up with high fuel costs and stiffer competition.

While a link-up of these airlines are widely expected to help air travelers, Virgin and its other critics say such cooperation could stifle competition, leading to higher ticket prices and fewer choices for consumers.

AMR Corporation's American Airlines, British Airways PLC and Spain's Iberia Líneas Aéreas de España SA are members of the 10-airline Oneworld alliance, which competes with the 21-member Star Alliance and the 11-member SkyTeam across their respective networks.

The planned alliance between BA and AA would ''severely damage competition on major transatlantic routes and leave consumers worse off,'' Virgin Atlantic said it a letter written to McCain and Obama.

''Airlines everywhere are struggling with the current price of oil, but the solution to their problems should not lie in an anti-competitive agreement which will inevitably lead to less competition and higher fares,'' Branson said in his letter to the two presidential candidates.

BA also is reported to have offered to surrender of its take-off and landing slots to win US backing for the planned alliance with American, the Financial Mail reported.

BA and American are seeking anti-trust exemptions from the US Department of Transportation for co-operating in areas such as ticketing. BA said it would make an announcement about co-operation with American in the next couple of weeks.

American and BA are allowed to share passengers on some routes, but they compete on flights between the US and London's Heathrow Airport and can't share commercially sensitive information on capacity or pricing.

Six SkyTeam members, including Air France-KLM SA, Delta Air Lines Inc. and Northwest Airlines Corp have teamed up in a similar alliance like the one proposed by American, BA and Iberia.

Continental Airlines Inc recently said it will switch to Star Alliance from SkyTeam as it expects to benefit in terms of traffic volume and global reach.

BA and Iberia also last month announced plans to merge while Delta and Northwest are seeking permission to combine.

Airlines are both aligning and realigning as the high fuel and operating costs increasingly eat into their revenues and profits.

The Star Alliance was formed after the 1997 merger of UAL Corporation's United Airlines, Germany's Deutsche Lufthansa AG and three other carriers.

SkyTeam and Oneworld followed three years later. Today, the alliances account for roughly two-thirds of world-wide air traffic.

Meanwhile, four British Airways executives - current and former - face up to five years in jail after being charged with price-fixing offences.

The four BA executives were charged with the criminal cartel offence on 7 August 2007, which makes it a criminal offence for individuals to participate in activities such as price fixing, market sharing and bid-rigging.

Those found guilty of the cartel offence face up to five years' imprisonment and/or an unlimited fine. They also face possible disqualification from acting as a director of a UK company.

The charges relate to a cartel between BA and Virgin Atlantic to fix the cost of fuel surcharges for long-haul passenger flights between 2004 and 2006. BA has already been fined £121.5 million for breaching competition law through its involvement in this cartel.