Russian flag carrier OAO Aeroflot (AFLT.RS) Friday signed a leasing agreement with Rostekhnologii, a Kremlin-controlled holding company that said the deal will guarantee a recent order from Boeing Co. (BA) that is worth up to $2.5 billion.

Rostekhnologii last year launched a tender for the planes on behalf of six regional airlines that it then owned, but the holding later ceded control of those companies to Aeroflot, which has been favoring Airbuses for its own fleet.

Boeing earlier this week beat Airbus to the Rostekhnologii tender for up to 65 planes, but the Russian holding--whose titanium business Vsmpo-Avisa is a major Boeing supplier--didn't say why it needed the planes after giving up the regional carriers.

Although Rostekhnologii hasn't said whether the deal with Boeing is binding, it now wants Aeroflot to take the planes.

In a joint statement, Aeroflot and Rostekhnologii, said they have signed an agreement to "cooperate in the purchase and lease of passenger planes."

Rostekhnologii adviser Roman Pakhomov said the holding will create an aircraft leasing company, possibly in partnership with a bank or state export agency, that will buy the planes and lease them to the six regional airlines controlled by Aeroflot.

"Unfortunately, no one can put it in a contract yet saying that Aeroflot will be buying the planes," he said, adding that he expects that to happen in autumn.

An Aeroflot spokesman said that the airline is still reviewing the strategy for the six regional carriers, adding that the agreement with Rostekhnologii requires the holding company to offer better leasing terms than other available proposals.

Aeroflot's own fleet of planes is made up of both Airbus and Boeing planes, but its US-made aircraft are mostly used for long-distance routes. It has orders in for Boeing 787 aircraft, which are delayed due to production problems.

Aeroflot hasn't yet confirmed that it will integrate the six regional airlines into its core operations--it wants to change their route maps first--but Rostekhnologii's Pakhomov said that it still makes sense for the airlines to buy from Boeing because it already use aircraft from the manufacturer.

Like Rostekhnologii, Aeroflot is controlled by the Russian government, but Russia's flag-carrier also has private shareholders, most notably Alexander Lebedev, the tycoon who recently bought loss-making U.K. newspapers The Independent and Independent on Sunday.

When Rostekhnologii gave up control of its six regional airlines earlier this year, some analysts said the government wanted to guarantee that Aeroflot had the financial muscle to support the Russia's domestic aircraft-making industry.

As well as Rostekhnologii's titanium supplies to Boeing, other state-controlled companies work closely with Airbus, and domestic manufacturer Sukhoi is making its own regional jet, the SSJ-100.

Russian newspaper Kommersant on Friday suggested that Rostekhnologii's commitment to Boeing was a political compromise, after the U.S. state department lifted sanctions on its Rosoboronexport business, which is responsible for all Russian military exports.

-By Will Bland, Dow Jones Newswires; +7 495 232 9198; william.bland@dowjones.com