SkyTeam plans to build a "more robust" alliance on the anti-trust immunity six of its members have been granted by the US Department of transportation (DoT).Nat Pieper, Northwest Airlines' vp alliances, said the approval meant SkyTeam could offer "something much larger" to its passengers.The DoT gave approval last month for closer co-operation between six carriers: Northwest, Air France, KLM, Alitalia, Czech Airlines and Delta Air Lines.Mr Pieper was speaking at a press conference to mark the launch of Northwest's inaugural flight from London Heathrow to Seattle. The carrier, in co-operation with its partner KLM, plans to run a daily service which will directly challenge the monopoly BA has enjoyed on the route for about 12 years. He said the Seattle service would be a connecting route onto the Pacific and the North West as well as a point to point service from London.Mr Pieper said Air France KLM and its partners now ran 100 direct flights from London to the USA.He said this was a “fantastic achievement for carriers not operating in their home market.”Mr Pieper said the SkyTeam alliance would be looking for more slots at Heathrow."Our four airlines together (Northwest, Delta, Air France and KLM) are the biggest airline force in the international market and to be this, you have to be a big player in London."There are a couple of avenues we are looking at for more slots that can be used for the international market and there is also the secondary market."The demand to fly to London is pretty strong from China and India. That secondary market is pretty strong," he said.Ms Christine Ourmieres, the UK general manager for Air France KLM, said the route had already been given a "very positive welcome" by the corporate market.Seattle is home to major global companies including Microsoft, Boeing, Amazon and Starbucks.She said there were already negotiations underway for corporate deals with companies on the new Seattle-Heathrow route.* For the full interview with Ms Ourmieres, please see BTE Analysis.