Kim M. Testa, a spokeswoman for Lockheed Martin, said that Canada would complete the procurement in 2014 and begin accepting delivery two years later.

Other nations have also debated the necessity of an aircraft as costly and sophisticated as the F-35. Opposition leaders in Denmark and the Netherlands are questioning whether they can afford to buy the plane at a time when their economies are under pressure. Lockheed, however, needs to hold onto the foreign sales to lower the cost of the planes.

The American defense secretary, Robert M. Gates, recently revamped the F-35 program and removed the general in charge, after the Pentagon’s projected costs soared 64 percent to $382 billion for 2,457 planes. The eight allies have invested a total of $4 billion in developing the plane and could buy hundreds of the planes through specific orders, most of which remain to be negotiated.

But Lockheed Martin’s chief executive, Robert J. Stevens, said in June that the company was cutting its costs and improving the efficiency of its production.

Though recent Pentagon estimates have placed the cost of a single F-35 as high as $112 million, Mr. Stevens said Lockheed believed it could lower the cost, by 2014 or 2015, to be comparable to updated and fully loaded versions of older fighters, like Boeing’s F/A-18 and Lockheed’s own F-16. That would reduce the price of each F-35 to about $65 million.

During the news conference, Mr. MacKay would not say how much Canada would pay for each jet. Although he did indicate that the 9 billion Canadian dollar figure includes other costs like training, improvements to airbases as well as simulators.

A Canadian procurement official, who spoke on the condition he not be identified, said that the government was assuming that it would pay 90 million Canadian dollars for each F-35 although it anticipated that the final cost would be much lower.