Canada's participation in the F-35 Joint Strike Fighter program with a multibillion-dollar future purchase is becoming embroiled in more controversy, with calls on Conservative Prime Minister Stephen Harper to come clean on the jet's final cost and capability.

"We now need the straight goods from the Conservatives on cost and capability," John Ivison wrote in the National Post.

"Is the F-35 affordable in the numbers we need? Do we need stealth? Does it really handle like a 'flying piano'?" Ivison asked in a reference to criticism the F-35 was too expensive for Canada and could be unwieldy in flight.

In a Foreign Policy magazine article, defense analyst Winslow Wheeler compared the fifth-generation Lockheed Martin fighter jet to a "virtual flying piano" because it lacks agility and is grounded far too often for maintenance.

The Canadian government recently designated a special secretariat to deal with the purchase but public skepticism over the deal is growing amid sustained media attention.

Canadian air force commander Lt. Gen. Andre Deschamps told a parliamentary committee the air force still wants the F-35 despite doubts about its capabilities.

Deschamps said he was "not perturbed" by "surprises" that are coming to light in the plane's test and development phase.

He told the public accounts committee the F-35 is the only plane that meets the air force's needs and the military isn't looking at alternatives.

Canada's Auditor-General Michael Ferguson issued a report criticized the government's handling of the F-35 program. The report said the Department of National Defense was overconfident in its ability to contain spending on the procurement, understated costs and didn't provide full information to Parliament.

Canada hopes to acquire more than 60 of the planes. Conflicting reports on the cost per plane have deepened the controversy. The cost estimates currently range between $85 million-$135 million.

Canada is planning to replace its aging CF-18 fleet with the F-35 but Parliament heard the costs for the 30-year life-cycle of the jets could be double the $16 billion cited by the government.

Wheeler criticized the F-35 in a Foreign Policy magazine article, calling it "simply unaffordable, behind schedule" and a disappointment in terms of performance.

"The F-35 is an unaffordable mediocrity, and the program will not be fixed by any combination of hardware tweaks or cost-control projects," Wheeler wrote.

"There is only one thing to do with the F-35: Junk it. America's air force deserves a much better aircraft and the taxpayers deserve a much cheaper one," wrote Wheeler.

Ivison wrote Harper's government "needs to restore some confidence in a process that has been undermined by some figures at National Defense who considered the strictures of operating in a parliamentary democracy to be too cumbersome and inconvenient."

The F-35 had its first test flight on Dec. 15, 2006, and has been in development since.

The United States intends to buy 2,443 aircraft to provide the bulk of its tactical air power for the U.S. Air Force, Marine Corps and Navy. NATO and U.S. allies that have committed to buy include Australia, Britain, Italy, Japan, the Netherlands, Norway and Turkey.

The U.S. spending on development and procurement is likely to exceed $323 billion, making it the most expensive defense program ever.

The total 50-year life cycle cost for the entire U.S. fleet already is estimated to be $1.51 trillion -- $618 million per plane, which is several times over the current unit price range.