UK airline bmi, the second largest slot holder at London Heathrow, is seeking an alliance with American carrier United Airlines.
The two carriers, both members of the Star Alliance, have renewed their application for anti-trust immunity to the US Department of Transportation (DOT).
The Department approved the previous application in 2002 on the conditions that a UK/US Open Skies deal was signed and it could review its decision when such a deal was agreed.
An Open Skies deal was agreed between the EU and the US last month, now bmi and United want the DOT to approve their anti-trust status.
United, one of the four airlines allowed into Heathrow under the old Bermuda II agreement, already has similar anti-trust deals with other Star partners, including Lufthansa.
If granted, a bmi spokesman said it would allow the two airlines to cooperate in various areas including codesharing, pricing, scheduling, sales and marketing.
The bmi move come at the end of a week of activity and rumour in the industry.
Bmi, which was also said to be the subject of a take-over bid by BA, sold some of its slots at Heathrow to that carrier for £30m.
This gives BA more than 41% of the slots at the congested airport.
US company Texas Pacific Group (TPG) put in a €3.4bn bid for Spanish carrier Iberia Airlines.
The move led to speculation that BA, a 10% shareholder in Iberia and a oneworld partner, might follow up with its own take-over bid.
TPG pursued its offer by asking for "corporate, accounting, tax and legal information" from Iberia.
BA withdrew its two directors on the Iberia board from its meeting last Friday to avoid a conflict of interest.
The Iberia board is expected to meet again next week, without the BA members, to discuss the TPG offer and its request for information.
BA has issued a brief statement saying it had appointed UBS to advise it.
"The advice will examine all options including a disposal of British Airways' holding," it said.
In perhaps the surprise move of the week, Aeroflot, the Russian carrier, said it would bid with the support of the Italian bank Unicredit, for Alitalia, the troubled Italian carrier.
The Italian government, which has a 49.9% in the chronically loss making airline, plans to sell at least 39.9%.
The deadline for bids is April 16.