A one-way ticket on the Heathrow Express, which takes passengers on a 17-mile journey between London's Paddington station and the west London airport, currently costs pounds 10. The airport operator British Airports Authority, which runs the service, said increasing prices at peak times was "an option".
BAA said that the service,launched in June 1998, carried 13,000 passengers a day - below its first-year target of 15,000.
The chief executive, Sir John Egan, said that business travellers did not consider the pounds 10 fare to be too high - some thought it too low. A range of prices might soon be introduced to attract more leisure passengers to the route.
Sir John added that Americans were giving the Heathrow Express the cold shoulder:"Apart from people from New York, Americans don't think trains are for respectable people," he said.
Sir John was speaking as BAA, which runs seven UK airports including Heathrow, Gatwick and Stansted, announced 1998-99 pre-tax profits of pounds 516 million - a 7.5 per cent increase on the 1997-98 figure.Reuse content