The Virgin Group's share will fall from a controlling 51percent to just 20percent.
Delta will retain 49percent.
Sir Richard is to remain "very much involved" after the deal, but more in a marketing/ PR capacity.
Jean-Marc Janaillac, chief executive of Air France-KLM, claimed the new partnership would give customers "even more choice between Europe, UK and the United States via twelve hubs on both sides of the Atlantic".
Virgin Atlantic and Delta have been code sharing flights as a joint-venture for over four years, targeting the sectors between Europe and the USA.
Now that the UK is leaving the EU, there are wholesale changes within the aviation industry with many airlines setting up EU based operating compnies so they can continue flying even if the UK fails to complete a brexit and trade deal, inside the current two year timetable.
This is coupled with increasing competition with a change in emphasis and service levels and type. Even the aircraft are different with new entrants featuring slim narrow bodied twin engine new generation aircraft.
Norwegian has made notable advances and the Spanish based budget ' Level' budget airline operated by British Airways service is offering long-haul flights.
With the uncertain news over Alitalia's future, with a possible restructure or liquidation now a distinct possibility. Alitalia is however currently part of the new venture, will daily operate some 300 transatlantic flights.
Virgin and its partners (in a statement seen by BBC News) said they would offer "convenient flight schedules with competitive fares and reciprocal frequent flyer benefits, including the ability to earn and redeem miles across all carriers".
In a blaze of publicity in 1984 Virgin Atlantic, was set up with one aircraft. Richard Branson's Virgin had a troubled birth and opened up an all out bitter commercial feud and price war with Lord King then boss of British Airways.
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