“There are a number of missions and training events that are not possible to achieve at the same time . . . There are days where we don’t have enough aircraft to do one of the missions,” Vance told reporters.

“It’s not just deployed missions that count. It’s deterrents. It’s the defence of Canada. It’s the ability to respond to another 9/11-type incident. It’s the ability to respond to the unforeseen,” he said.

Foote made clear that the Super Hornet — a larger, heavier and upgraded version of the CF-18 — is Canada’s favoured choice. But she refused to say how much Canada may have to pay for the jets.

“We have a sense of what the cost will be, but we have to enter into negotiations with Boeing,” she said.

The decision also means that the government will have to spend tens of millions of dollars more on upgrades necessary to keep Canada’s old fighters safely in the air until the late 2020s.

But even then, federal officials say interim jets are needed as an insurance policy. “No one in the world has flown them that long,” Sajjan said.

Tuesday’s announcements betrays one Liberal campaign promise — Prime Minister Justin Trudeau’s vow not to buy the Lockheed Martin F-35 jet — and undermines another, namely the commitment to go with a less-costly fighter to free up “tens of billions of dollars” for investment in the navy.

Foote said Tuesday it would be an “open” competition, suggesting that F-35 maker Lockheed Martin would allowed to bid.

And it wasn’t clear how much Ottawa would be spending on fighter jets. Ministers refused to discuss how many jets would be purchased as the permanent replacement, saying that decision would await the outcome of the defence policy review now underway.

But the government’s move to go with the Super Hornet drew criticism Tuesday. Conservative MP James Bezan accused the government of “wasting” billions of dollars and in the interim, saddling the air force with the wrong jet.

Noting that the previous Conservative government had determined that a fleet of 65 F-35s could meet air force needs, Bezan said the 77 CF-18s should be up to the task. “There is no capability gap,” Bezan said.

“They’re punting a decision till after the next election. This is all political manoeuvring,” Bezan said.

Defence analyst Dave Perry questioned whether the Liberals’ election vow not to buy the F-35 was behind the announcement to delay a decision for years.

Perry, a senior analyst with the Canadian Global Affairs Institute, said he’s not convinced the interim fix is even necessary.

“I think they could have announced a competition today and had aircraft actually in service in not much longer a time span without the additional cost of operating two fleets,” he said in an interview.

Sajjan claimed that the Liberals “inherited” the situation and pointed the finger at the previous Conservative government which he said had botched the purchase of fighters that should have purchased long ago.

Yet the ministers say the Liberals’ own search for a permanent replacement will take at least five years, pushing a decision back until after the next election.

Foote justified the length of time, saying that government intended to consult widely with industry and foreign governments. “We’re not about to cut corners and try and simplify a process that can be very complex,” she said.

The previous Conservative government had originally announced its intention to buy F-35s in 2010, but then put that decision on hold in late 2012 after the auditor general flagged concerns about the potential price tag.