The joint venture signed yesterday (October 17) between Air France and Delta Air Lines is a historic one.
Not only does it challenge the current structure of the transatlantic air market but it also acknowledges the increasingly powerful presence in Europe of the high speed train in the short haul market.
It is a deal in which a major European carrier consciously has opted to chase the long haul market at the expense of its services in short haul.
It is a deal that will finally end the hegemony that four airlines, BA, American Airlines, United Airlines and Virgin Atlantic have long enjoyed on the lucrative New York-Heathrow route.
And it is a deal which is also likely to force other carriers to re-assess their long haul operations on the transatlantic routes.
Both Jean-Cyril Spinetta, president and ceo of Air France KLM and Richard Anderson, ceo of Delta, readily acknowledged that the joint venture was only made possible by the Open Skies deal signed this year between the US and the EU.
When that comes into force next March, any European or American airline which can get a slot at Heathrow can start a service from there to New York. Delta is the first to have broken in - but it is not likely to be the last. Continental Airways is also keen to start such a service and Virgin just might emerge as a potential partner.
Delta's new services out of Heathrow will create a little more choice and competition on this route which, as Mr Anderson pointed out, links "the two top business destinations in the world."
But there is another aspect to this deal. To provide Delta with its three slots (and also one for itself to start a Heathrow-Los Angeles service), Air France is cutting its Heathrow-CDG services from 12 to eight or possibly seven a day.
The airline candidly admitted it was making these slots available because of the success of Eurostar's high speed train service between London and Paris. It was an acknowledgement that this short haul market in Europe is switching increasingly towards the use of trains.
The cut from 12 flights a day to eight or possibly even down to seven is substantial, more than 30%. Clearly Air France, having watched Eurostar take more and more passengers on the London-Pairs route, decided that its position would be further weakened when the train company moves to St.Pancras next month.
From there, journey times between the two cities will be cut by 20 minutes to 2 hours 15 minutes - in continental terms completely a train trip.
Air France which has had more experience in combating the impact of high speed trains services than any other airline in Europe, saw that the balance was inexorably shifting, that passengers would opt for the train and that the precious slots at Heathrow could be put to more profitable use.
But Air France executives stressed to BTE that the carrier was not abandoning its London-Paris services. Those operating from Orly to London City will not only be retained but increased, one executive said.
As to the joint venture itself, both airlines were reluctant at the press conference to go into too much financial detail, although they spoke of margins of between $150m-200m.
The deal will be managed by a steering committee made up of representatives of both carriers which will meet at least quarterly but be in touch on a daily basis.
But staff will not, at least for the time being, be integrated.
The aim will be to provide similar levels of service which will mean co-ordinating aspects like sales and distribution policies, onboard services, revenue management, frequent flyer programmes, IT and finance.
They envisage that by the end of 2016, the combined revenues of the joint venture will be $8bn. They will also by then be effectively operating as one airline on transatlantic routes.
But the vision does not end there. If the US Department of Transportation approves, as expected, the application by SkyTeam members for anti-trust immunity next summer, Air France, KLM, Delta and Northwest Airlines will start talks.
These will be aimed at extending the joint venture to cover all four carriers on transatlantic routes. These four airlines will be a major player on these routes.
If nothing else, this new deal will cause Star Alliance, led by Lufthansa and United, and oneworld, led by American Airlines and BA, to take stock.
The Air France Deltas deal has opened up the way to what could be major changes. The next few months could prove interesting as their rivals seek to combat these developments.