The F-35 has no clear edge over three other fighter jets Canada is considering to replace its aging fleet, a declassified government-commissioned report says.

The analysis found the Lockheed Martin F-35 Lightning II Joint Strike Fighter, Eurofighter Typhoon, Dassault Rafale and Boeing Super Hornet to be capable of accomplishing most mission tasks envisioned by Canadian military leaders.

The only exception would be going to war with another state, but the reports' authors concluded that was an "exceptionally unlikely" scenario.

"It is very unlikely Canada will be the target of overt, hostile state-directed military aggression," said the report released Wednesday.

To date, Canadian fighter jets have been mostly tasked with securing Canadian and US airspace from intrusions as part of the North American Aerospace Defense Command (NORAD).

Over the next three decades, they will also likely participate in allied bombing missions or enforce no-fly zones over foreign soil such as in Libya and Iraq, intercept hijacked aircrafts and provide security for humanitarian assistance drops, the report said.

Domestic patrols involve a "relatively low level of threat and are less onerous for fighter aircrafts," it said, adding all four jets under consideration would do a fine job.

In a war, however, one of the aircrafts under consideration would fare much better, notably against futuristic anti-air defenses.

The report does not identify which plane is best or worst for Canada's defense needs.

F-35 proponents have said the stealth fighter jet is the only one capable of countering threats by advanced militaries.

In 2012, Canada widened its multibillion-dollar search for a new fighter jet to models other than the F-35 it had spent 15 years helping the United States and other allies to develop.

Ottawa took this step after the largest procurement in Canadian history came under fire over its spiraling costs and an apparent lack of transparency and competition in the process.

Opening up the process to bidding, however, does not preclude Canada sticking with the F-35, which the government and the military still appear to favor.

A purchase decision is not expected until after next year's general election.

Canada's fleet of CF-18 fighter jets was due to be retired in 2020. But the government has ordered an upgrade to keep the CF-18s flying through 2025.