BA, American Airlines (AA) and Iberia are in talks over a joint application for anti-trust immunity from the US Department of Transportation (DoT).
A BA spokesman confirmed the talks which he said had been going on for "some time."
But he dismissed as "pure speculation" a report that BA ceo Willie Walsh and his AA counterpart Gerard Arpey were meeting the US transport secretary later this month.
The three oneworld alliance partners are aiming to set up a joint venture to share profits and revenues on transatlantic routes.
If such the scheme went ahead it would create one of the most powerful airline collaborations in the world.
BA, AA and Iberia would be following in the steps of SkyTeam members Air France and Delta Air Lines and KLM and Northwest Airlines which are already running joint ventures on transatlantic routes.
Efforts by BA and AA, two of the major players in the lucrative transatlantic market, to work more closely in the past have been rebuffed by the DoT.
But the three airlines believe that with the soaring cost of fuel and the impact of the first stage of the Open Skies agreement between the US and the EU, circumstances have now changed in their favour.
The Open Skies agreement has allowed any airline to fly transatlantic routes out of Heathrow, a route previously limited to just four carriers, among them BA and AA.
The move has already been criticised by BA rival Virgin Atlantic.
Paul Charles, its communications director, said: "We would oppose this attempt to create an anti-competitive alliance.
"It would form a dominant mega-power on transatlantic air routes from two of the largest EU members, forcing up ticket prices for passengers and restricting choice.
"BA/AA/Iberia would together dominate slots at Heathrow Airport and use that power to block new entrants onto key routes in Europe and across the Atlantic.
"The current crisis in aviation must lead to survival of the fittest, not protection for the fattest. Regulators must block this attempt to create such a giant champion of anti-competitive behaviour."