Canada's newly appointed top military officer says it's important to get it right when it comes to replacing the Canadian Forces' aging fleet of CF-18 fighter jets -- equipment he said the military will rely on for decades.

Lt.-Gen. Tom Lawson was promoted to general on Monday and officially installed as chief of the defence staff, succeeding Gen. Walt Natynczyk, who is retiring after four years in the role. Natynczyk has described his replacement as "a great officer and a gentleman."

Lawson spoke with CTV's Canada AM Tuesday about the challenges that lie ahead.

Unlike his predecessors, Natynczyk and Gen. Rick Hillier before him, Lawson inherits a military that is not involved in an active combat mission. Instead of running a war mission, Lawson said he will be instead focusing on bringing Canada's servicemen and women home and ensuring the Canadian Forces is prepared for future "challenges."

Among those challenges, he said, is to find a replacement for Canada's fighter jets, a project he suggested is vital to the military's future.

"It's a big project, and we have several on the books -- we have, of course, the national ship-procurement strategy underway as well -- and we have to get these things right. The Canadian Forces will be living with this equipment we'll be buying for decades, a generation and more," Lawson said.

He said the Canadian Forces' role in the CF-18 replacement project is to provide advice about military needs, as well as offer feedback on the various options brought forward by the public works secretariat leading the search. "I'm really pleased it's a whole government effort because I think Canadians, by and large, can become more comfortable with the process," Lawson said. The federal government has faced tough criticism for heavily favouring the Lockheed Martin F-35 stealth fighter as its top choice for the military.

The opposition has said the replacement program should have been put out for public tender to keep costs competitive, while the Conservatives say the F-35 is the best jet for Canada's needs -- and by joining the U.S. and other partners in a major purchase, Canada can save millions. Ottawa has so far invested $335 million in developing the multi-use jet.

On Tuesday during question period in the House of Commons, opposition members asked for a clear answer on which planes were under consideration.

Public Works Minister Rona Ambrose didn't give specifics, but said a committee was looking at the issue and the government was hiring independent consultants to help.

"We want to get this right. We have not spent any money on the acquisition of any aircraft to replace the CF-18 and we will not spend any money until we do the full due diligence, that is what these firms are hired to do," Ambrose said.

When the question was repeated, Ambrose again declined to name specific planes that were being considered.

"The member knows full well we've set up the National Fighter Procurement Secretariat to ensure full transparency and due diligence of our seven-point plan," Ambrose said, adding that the government has agreed to provide regular cost updates to Parliament.

"We want to make sure we have all the information on the table, all the information available before we make a decision," she said.

Last week, National Defence issued a statement refuting comments from Lt.-Gen. Yvan Blondin, the newly appointed head of the air force, who said he has not yet been ordered to complete a detailed study of any options other than the F-35.

National Defence responded by saying other options were being looked at and "information shared with a reporter was incorrect."

Canada committed to buying 65 of the fighter jets in 2010, but was forced to back away from that plan following an outcry from the public, opposition, and a report from Canada's Auditor General Michael Ferguson, which said the government had lowballed cost estimates for the purchase by as much as $10 billion.

Defence Minister Peter MacKay has said the discrepancy comes down to a simple difference in accounting: While Ferguson factored in such costs as the jets' fuel and lifetime upkeep, the government did not.