We are already spending billions on a F35 with the money going to the US. Don't forget the technology is available and I'm certain we already have and attract the talent.
So what evidence do you have to say it can't be done.

One idea that should be revisited and revitalized is the concept of the Avro Arrow. A Canadian state of the art fighter redesigned for the century. Bombardier is a good candidate to accomplish this in cooperation with other Canadian based companies perhaps in the automotive sector.