Northwest Airlines will start three new services from Heathrow next year after acquiring slots at the London airport from its partner KLM.
It is the fourth US carrier to announce new transatlantic routes from the airport since the signing of the EU-US Open Skies agreement earlier this year. It comes into force next March.
The three earlier carriers were US Airways and Northwest's fellow SkyTeam members Delta Air Lines and Continental Airlines.
Northwest's three new destinations to be served daily are:
* Minneapolis/St Paul which is being shifted from Gatwick and will start at Heathrow on March 29
* Detroit which will start on May 1 although NWA will still run services to the city from Gatwick
* A new service to Seattle which will start on June 2.
Nat Pieper, Northwest's vp for alliances, said the slots had been leased from their joint venture partner KLM.
Pieter Elbers, KLM's senior vp network for KLM, said his carrier would provide the slots by reducing from three to two a day its flights to Rotterdam and shifting its two daily Eindhoven flights from Heathrow to London City.
Mr Pieper said the flights would be on new A330 aeroplanes which were less expensive to run and more environmentally friendly than aircraft it has previously used.
He said that in the past two years, there had been a 40% increase in transatlantic flights from 200 to 275 a week by the NWA/KLM joint venture.
Mr Pieper said the Heathrow-Seattle flight would be in competition with BA, the only other carrier to do that route non-stop.
It is a route heavily used by business travellers with two of the world's biggest companies, Boeing and Microsoft having their headquarters in the city.
All of the new services will go from Heathrow Terminal Four which SkyTeam is taking over after BA moves out to the new Terminal Five next year.
Northwest is in negotiation with another, unnamed airline to take over for next summer at least the slot at Gatwick vacated by shifting the Minneapolis/St. Paul service to Heathrow.
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