From the second article you linked:
> Should Canada have acted when it flew into Canadian airspace?
> The short answer, according to military experts, is no.
> "To say that, oh, Canada should have shot this balloon down on its own — that's just silly," said University of Calgary history professor and military historian David Bercuson.
> "That just completely ignores the fact that NORAD exists that we're part of it and have been part of it for almost 80 years now."
And yes, it also says this:
> The operating altitude of Canada's CF-18 Hornet fighter jets is 50,000 feet (15,000 metres), while Pentagon press secretary Brig. Gen. Pat Ryder said the balloon had been flying at about 60,000 feet (18,000 metres) — potentially out of range for those jets.
However that ignores the fact that the F22 that shot down the balloon did so from 40,000 feet. Using a similar missile, a CF-18 certainly could have done the same.