The legalization of recreational marijuana in Canada is only two weeks away.\nBut as Candians consumers, government regulators, and corporations prepare for the sudden launch of a new industry, so, too, are American law enforcement agencies.\nALSO READ: The Government Of Canada Has Already Predicted That We'll Run Out Of Legal Marijuana Supply By Next Year\nTL;DR Canadians who transport cannabis through American airspace on domestic flights are taking a serious risk. Here are the potential consequences.\nDespite the legalization of cannabis in several U.S. states, the drug is still illegal under federal law and the subject of especially critical scrutiny under the administration of Donald Trump.\nThe U.S. Customs and Border Security agency has promised to make no exceptions for Canadian cannabis possessors. Canadians who admit to marijuana use face lifetime bans from entering the United States.\nSince Canada maintains so many economic connections with the U.S., such regulations and bans can pose challenges, particularly when it comes to travel.\nYesterday, news broke that Canadians will be able to carry marijuana on domestic flights after legalization.\nBut what about domestic flights that pass through U.S. airspace?\nFlights between Montreal and Vancouver, and Toronto and Halifax, for example, cross the American West and Northeast, respectively.\nOn such flights, transporting cannabis is a serious legal risk.\nA spokesperson from the U.S. Customs and Border Protection agency (USCBP) told MTLBlog that "crossing the border or arriving at a U.S. port of entry in violation of this law may result in denied admission, seizure, fines, and apprehension."\nHe continued: "any arriving alien who... admits having committed, or admits committing, acts which constitute the essential elements of a violation of (or an attempt or conspiracy to violate) any law or regulation... is inadmissible to the United States."\nSo while Canadians domestic flights in American airspace are exempt from U.S. federal law while they are airborn, they do pose a potential security risk.\nWere those planes to make an emergency or otherwise unscheduled landing at an American airport, passengers would need to pass through U.S. customs. Those passengers transporting cannabis would be punished accordingly.\n@customsborderembedded via\nThe most likely scenario would be a lifetime entry ban and quarantine until officials could arrange a flight back to Canada. Fines and arrest are more severe possibilities, presumably depending on the quantity of cannabis.\nBut domestic flights over American airspace also present challenges for Canadians even before departure.\nAccording to the Federal Aviation Commission, the government agency that manages air travel in the U.S., all flights that pass through American airspace are required to forward a passenger manifest.\nCanadians who have already received lifetime bans from the USCBP could be kicked off their flight at the demand of U.S. officials.\nCanadians with cannabis associations could consequently face domestic travel restrictions in addition to travel bans from American authorities.\nRecreational marijuana legalization has had some unforeseen consequences.