Canadian defence officials have strongly made the case that Ottawa should stick to a plan to buy 88 Lockheed Martin F-35 fighter jets rather than splitting the order, two sources familiar with the matter said.

The review stops short of making a formal recommendation, one of the sources said.

The final decision rests with the Liberal government of Prime Minister Mark Carney, said the sources, who requested anonymity given the sensitivity of the situation.

Canada unveiled the $19-billion (US$14-billion) deal in early 2023. But in June, Canada's top independent watchdog said buying the jets would cost at least 45 per cent more than initially estimated and said the project was also threatened by a pilot shortage.

Carney, who won the April election on a promise to stand up to US President Donald Trump, had requested the review by military officials in March on the grounds that Canada was over-reliant on the US defence industry.

Ottawa has made a legal commitment of funds for the first 16 F-35 aircraft. Although Carney made clear in March that Canada could seriously look at buying the remaining 72 planes from non-US companies, the Defence Ministry review concluded there was no military sense in splitting the order.

The F-35 is the most advanced fighter of its type, and buying another jet from a European rival would incur extra costs in training, supplies, and maintenance. The Canadian Armed Forces are highly integrated with their US counterparts.

Sticking to the original plan could remove a potential irritant in relations with the United States at a moment when talks on a new trade and security relationship have stalled.

Since winning the election, Carney has softened his tone, noting that despite US tariffs on steel, aluminum, and cars, Canada is in a good position compared to other nations facing higher tariffs.

In a statement, the office of Defence Minister David McGuinty reiterated that Canada planned to buy a new fleet of advanced fighter jets.

"In all defence procurement decisions, our government will prioritize defending Canada and Canadian sovereignty, while supporting Canadian industry wherever possible," it said. 

"We are committed to procuring what the air force needs, while ensuring economic benefits for Canadians and the responsible use of taxpayer dollars."

Carney's office declined to comment.

Canada announced plans to buy the F-35s in 2010, but a switch in governments, rule changes for aircraft procurement, as well as challenges from the pandemic, triggered major delays.

Spain is no longer considering the option of buying F-35 fighter jets and is choosing between European-made alternatives, a Spanish Defence Ministry spokesperson said this week.