Marijuana will be legal in Canada beginning in July, 2018. Despite that, Transport Canada medical authorities and regulators say it will still be illegal to fly with ANY level of THC in the blood. So zero tolerance will be the norm.

If a pilot is randomly tested and THC is found, his license could be revoked for as long as it takes for all traces to be out of his system.

So the memo to all Canadian pilots reads as follows: "If you want to keep your wings, best rely on your engine power to get high."