[namirez]

Fair point, but these kinds of cancellations are not unusual. For example, YF-23 and X-32 were both cancelled due to losing the competition to YF-22 (later F-22) and X-35 (later F-35), respectively. So individual designs were cancelled, but not the original mission request.

Although all those programs were cancelled, both US and Soviets built a bunch of interceptors in the 60s and 70s, notably F-106 Dart and Su-15.

[tolien]

The YF-23 and X-32 were losing competitors in a program that went ahead, though.

The entire concept of high altitude supersonic nuclear bombers died, and with it the idea that you’d need/be able to intercept them. The UK offered Canada the English Electric Lightning instead of the Arrow - an aircraft that would do Mach 2 in level flight but only had a combat range of 135 miles (and that’s an F.6 with ventral and over-wing fuel tanks). 15 years after the Arrow was cancelled (4 years after the B-58 was retired, 18 years before the Lightning was retired but around the same time the RAF began phasing it out of service), the AGM-86 ALCM, with a range of 1500+ miles, went into development - neither aircraft would have been able to reach, never mind attack, the launch platform for those.

The successor to bombers like the B-58 and Valkyrie are mostly ICBMs/SLBMs but also things like the B-1B (launching stand-off missiles) and B-2. As the sibling points out, the Arrow didn’t have the range, RADAR or missile technology to counter those, and couldn’t use its few advantages (speed and altitude) that it would have cost a fortune to develop.

[ckozlowski]

The F-106 was actually the '54 Interceptor, and predated Arrow. It was the last "pure" interceptor that the U.S. built, as the F-108 and the A-12 (Blackbird-based) interceptors, both in the Arrow's performance class, were canceled.

The Arrow, while impressive in performance, wasn't without it's faults either. The requirements were far ahead of their time, and for some, wern't close to being met. The Nav/Radar systems, which to have "look down, shoot down" capability (i.e, Pulse Doppler). The missiles would the first fully active homing missiles in the world, having taken on the Sparrow II project that the U.S. Navy canceled.

As ballistic missiles, and not bombers, began to be seen as the danger coming over the pole, Arrow was questioned as it's entry into service was still a long way off. There was a lot more needed to be done besides flying high and fast; and something it's fans often overlooked. There were existing aircraft that could fulfill the now more limited role for far cheaper, and so it was cut.

It might have been for the best. The pulse-doppler radar it was to carry didn't come about until the later 60s with the latter F-4 Phantom versions, and the first fully active radar homing missiles not until the F-14 Tomcat/Phoenix/AWG-9 combination, which was huge. (The Active Sparrow that the U.S. Navy tried to get wasn't realized until AMRAAM of the 80s; relying on semi-active Sparrows all the way through the 90s.

One could make the argument that Canada should have dumped money into it anyway. Whether this is the "sunken cost" fallacy or promoting an industry I think is something of an opinion, but what I don't think happened is a U.S. plot to cancel Canada's project. The U.S. assisted in the development of it's engine and shared it's tech to date with the Sparrow II. But those technologies were not a good value for the U.S. defense budget at the time, and so they had lest justification as part of Canada's

Edit: Good article - http://airvectors.net/avarrow.html