The federal government plans to spend $8.3 billion to purchase 21 new aircraft for the Canadian military as part of a $17.1 billion cash injection, Defence Minister Gordon O'Connor announced Thursday.

"If we hadn't moved on this project and moved now, the capacity of the Canadian Forces to provide tactical airlift beyond the year 2010 would have been almost eliminated," O'Connor said of the 20-year investment.

"This in turn would have jeopardized Canada's ability to support our forces on domestic and international operations."

O'Connor was at CFB Trenton in Ontario on Thursday for the fourth-straight day of military spending announcements to update the Armed Forces' air, land and sea equipment.

His shopping plan includes four strategic aircraft, which are designed to carry heavy cargo or large groups of people and will cost a combined $1.8 billion.

The 17 tactical aircraft, which will cost $3.2 billion, will replace the military's current aging Hercules fleet, which is gradually being retired.

The remaining $3.3 billion will be spent on maintenance and contract costs.

"Because of its frequent need to cover tens of thousands of kilometres, the Canadian Forces need long-range strategic lift capability," he said.

"Strategic lift is the best and most efficient way to cover vast distances. It reduces the number of crews necessary for the journey. It reduces the number of stopovers for our aircraft and it is cheaper on fuel. Strategic lift is simply a logical option for the Canadian Forces."

In Edmonton on Wednesday, O'Connor unveiled a plan to spend at least $2 billion to purchase 16 military helicopters.

On Tuesday, O'Connor outlined plans to purchase 2,300 new high-tech trucks, and on Monday, unveiled a $2.1-billion plan to build three navy supply ships.

O'Connor told CTV Newsnet he anticipates the military to see the first new strategic aircraft in 2007, while the tactical aircraft, helicopters, and trucks are expected in 2008.

"Somewhere in the next two years, you are going to see a lot of this equipment starting to appear, the ships (will take) longer because we are building them in Canada ... and it's going to take us six years for us to get the first ship," he said.

Thursday's announcement came amid accusations that the Conservatives have already chosen the Boeing C-17 for its strategic airlift planes, despite claims of a transparent bidding process.

But military analysts believe two American manufacturers are already the favourites -- Boeing for the strategic airlift and Lockheed Martin for the tactical aircraft.

O'Connor was tight-lipped about the potential supplier, pointing to the government's Advanced Contract Award Notice (ACAN), which allows Ottawa to announce its intention to buy from one supplier, while leaving time for others to put in a bid showing they can also meet the necessary requirements.

But when pressed by reporters, O'Connor couldn't name any aircraft other than the Boeing C-17 that meets the requirements.

Despite the fact O'Connor refused to confirm that the C-17 had been chosen, Airbus Military issued a statement Thursday expressing disappointment its own airlifter, the A400M, had been ruled out.

"We are disappointed the government did not respond to the recent proposal we submitted to meet the Canadian military's airlift needs using our new 21st-century versatile airlifter, the A400M," said Richard Thompson, Airbus Military's senior vice-president, commercial.

"We will be reviewing all our options in the wake of today's announcement."

Canada's military has been flying Lockheed Martin's Hercules planes for more than forty years - and many believe Ottawa will buy the most recent version of this workhorse from the company.

"It's a great airplane to fly -- the Herc -- it's a stalwart plane. It's wonderful to fly. It's very forgiving," said Maj. Mike Graham, a Hercules pilot.

The Liberal Opposition, though, says the Conservatives have not done enough to make sure the Canadian companies benefit from these multi-billion dollar contracts.

"They've abandoned the idea of sovereignty and control ... they've outsourced our sovereignty and control," Liberal defence critic Ujjal Dosanjh said.

Earlier, O'Connor dismissed rumours he and Chief of Defence Staff Gen. Rick Hillier disagreed over which contractors will supply the military equipment.

"This is a myth. There hasn't been any disagreement between Gen. Hillier and myself. We're of the single mind of what we require for the Canadian Forces," he told CTV's Canada AM on Wednesday.

"He has my full support. The Cabinet has his full support and we're getting what the Canadian Forces need, including strategic and tactical transport."

Hillier agreed, saying O'Connor has his full support.

"I don't care which aircraft it is," Hillier said.

"I just want the capacity so that those men and women standing behind me here can do the job that our country asked them to do."

With a report from CTV's David Akin and files from The Canadian Press