The friendly skies just got a little friendlier.

The Transportation Safety Administration updated its policy last month to allow medical marijuana to be taken on commercial flights.

The change is significant because although cannabis for medical use is now legal in 40 US states and the District of Columbia, it remains outlawed at the federal level, which has jurisdictional control over the nation’s airports.

It comes after the Trump administration signed an order reclassifying marijuana as a Schedule III drug, effectively acknowledging that it has known medicinal uses and allowing medical research at a federal level.

Doctor-prescribed weed is now formally allowed on flights, both within customers’ checked and carry-on baggage, according to the TSA website, which says it’s more concerned with thwarting potential safety threats than narcing on passengers’ stashes.

“TSA’s screening procedures are focused on security and are designed to detect potential threats to aviation and passengers,” the policy revised April 27 spells out.

“Accordingly, TSA security officers do not search for illegal drugs, but if any illegal substance or evidence of criminal activity is discovered during security screening, TSA will refer the matter to a law enforcement officer.”

The agency notes that the TSA officer on duty at the time has the final say over whether an item is allowed through the security checkpoint.

Lawyers told SFGATE that officers rarely prosecute travelers for bringing small amounts of cannabis on their flights, but bringing more than an ounce might be pushing it.

Some passengers who really push the envelope could still wind up in cuffs, like a 23-year-old Texas stoner who was nabbed at Miami International Airport in March with 75 pounds of the devil’s lettuce in his luggage and was hit with a trafficking charge.

TSA did not immediately return a request for comment from The Post.