Online travel bookings in the US grew by 25 per cent over the past 12 months, according to data from Jupiter Research, which predicted that a third of US travel sales will be made over the internet by 2010.

Online travel spending for both leisure and business is expected to reach $68bn this year and rise to $104bn by 2010.

Growing numbers of online consumers, and increased awareness of the services on offer, are expected to drive nine per cent compound annual growth in the sector over the next five years.

The research also indicated a gradual trend towards buying direct rather than through travel aggregator sites.

Consumers will book 56 per cent of travel this year directly on supplier websites, instead of online travel agencies such as Expedia and Travelocity. That figure is predicted to increase to 62 per cent in 2010.

Although only three per cent of those surveyed used fare aggregators such as Sidestep and Kayak.com (also known as 'metasearch engines'), Jupiter Research predicted that the use of such sites will increase as suppliers try to attract more business to their own sites and price comparison becomes more appropriate.