Is he now on the lists of people banned from flights or from re-entering Canada?
Any Joe Sixpack convicted of a firearms offence involving commercial air transport would immediately be added to such lists, regardless of any effect it might have on his job. He would not be allowed to fly again on commercial flights. Someone from another country with such a conviction would be banned from entering the USA. The same should apply to Americans who commit felonies elsewhere and in particular there should be no special dispensation for a pilot convict. Pilots should be setting an example to the general public.
At the very least this convict should not be allowed on any flight into, out of or over Canada and should not be permitted to re-enter Canada. The travelling public has the right to expect that the laws and rules regarding offenders will be evenly applied to all.