For Canada:
- Build the Avro Arrow
This one is so obvious it drives one nuts. Expensive? Yes. The most capable interceptor in the world at the time and fully capable of decades of RCAF service? Most definitely. Does it massively build Canada's aerospace industry instead of forcing all of them to go to the US? Again, yes sir.
- CF-104 Phantom instead of CF-104 Starfighter
So obvious it's idiotic. If possible, have Spey Phantoms and have them made in Canada by Canadair or Avro Canada. Have a competent attack aircraft force until the 1960s.
- Barbel Class in the 1960s instead of the Oberon class
The Barbel has a longer-range and better sensors. In terms of noise level its a tossup between them. These should arrive in the mid-1960s, preferably built in Canadian dockyards, and last until the SSNs replace them in the 1990s.
- Shorts Belfast instead of the Lockheed Hercules
Aside from my own intense dislike for Lockheed in every way possible, the Belfast is the better plane for the job, with a greater payload and range. Again, could be possible to make these in Canada.
- TSR-2 or F-111 in the mid to late 1960s
Both aircraft would be mighty useful for the RCAF in the 1960s as long-ranged strike aircraft, useful for the anti-Warsaw Pact roles they will undoubtedly have in the 1960s. Establish a base in Britain for these if possible. Considering Canadair's closeness with General Dynamics and McDonnell Douglas, you can get F-111s made in Canada.
- Build the CL-84 as an attack helicopter
The Americans are just coming up with the AH-1 at this point in time, take the systems of the Dynavert and integrate it into the CL-84. You have just made one of the most dangerous attack aircraft in the world. Twice the speed and 50% more range than the AH-1, and all of its capabilities as a weapon hauler.
- Replace the Bonaventure in the 1970s (Invincibles or something like them, ideally)
I think its a little much to expect Canada to stay with full-size carriers by this point, but Invincibles would be on the cards and would be a great addition to the fleet. Ideally, take the Invincible design and stretch it from 209 m to 250 m, thus giving additional room for aircraft - the shipyards can handle it, steel is cheap and you get better ships as a result. Make sure Harrier IIs come with it.
- Argus II. Make it happen.
The Canadair Argus fleet was running out of life by the end of the 1970s and needed to be replaced. The Orion wouldn't be made in Canada, the Nimrod wasn't the best plane out there. Realistically, this is where a replacement needs to be made. I'm thinking a BAe 146 airframe with British, American and Canadian electronics in it.
- Hide the Canadian Caper until we've bought Iran's Tomcats
You get great planes at a fraction of their retail price, help the Middle East a bit and still get to show off our ability to do the right thing, not to mention give a rousing "f**k you" to the mullahs. If possible, buy up the Kidd-class destroyers at the same time. Use the Tomcats to retire the Arrow, but make sure Avro Canada gets a new job to do in the meantime.
- Nuclear subs in the 1980s
Trafalgar class subs, remind the Americans that they really want our help in NATO and that it would be good for us to have these things, so don't whine so much about it. If it'll get 'em to shut up, equip them with Mark 48 torpedoes and sub-launched Harpoons and Tomahawks.
- Better tanks in the 1980s (Leopard 2, Challenger 2 or M1 Abrams)
The Leopard C1 was obsolete by 1990. Better to get a good tank design and build it in our own plants, so that we can make more if needed.
- The Polar 8 Icebreakers
The biggest and baddest icebreakers in the world are the sort of thing that Canada should have. We need to be able to guard the Northwest Passage, and while the SSNs are good for defending it, the Polar 8s would make it quite obvious who owns it. If the SSNs are on deck at the same time, have the Polar 8s run on nuclear reactors as originally planned, and make sure they have the helicopters and hovercraft for them to work properly.
- Buy the AW101s in the 1990s
The AW101 cancellation was dumb IMO, and the helicopter has been able to be modified into multiple roles with different purposes, which is always a benefit for the fleet. 75 AW101s for Navy ASW, 20 for Search and Rescue and 15 for Arctic operations.
- Replace the Iroquois class destroyers in the late 1990s
By the 1990s they are obsolete, and Canada needed new ships by this point. The Kidds would probably work for a while for air-defense. By the late 1990s, though, we'd need something better - and at this point, AEGIS ships are in the cards. I'm thinking something similar to the Japanese Atago class, but with the hull lengthened in the tail for a larger helicopter hangar and helicopter deck.
- V-22 Osprey. Buy it.
All development problems aside, the Osprey is the best damn thing Canada could have for its Search and Rescue abilities. Having Canada involved in its development (hell, how about having more of NATO know about it) might allow us to help with development costs and perhaps some of the problems. This assumes, of course, that nobody developed the Dynavert design into a troop hauler in the meantime....