No. You cannot fly with cannabis across state lines in the United States. Air travel sits under federal jurisdiction, marijuana is a Schedule I controlled substance under the Controlled Substances Act, and neither a state legalization law nor a state medical card reaches the airport, the aircraft, or the airspace between two states. That answer holds when both states have legal programs, and it holds when you carry a small personal amount.
States control what happens on state land. Airports with commercial service, the aircraft, and the airspace above them are regulated at the federal level. TSA, the FAA, Customs and Border Protection, and the DEA all operate under federal authority, so a security checkpoint is a federal screening environment rather than a state one. Federal law contains no medical or recreational exception. Possession at a checkpoint is treated the same in Denver, Seattle, or Boston as it is in a state with no program at all. Adding a state line to the trip adds an interstate element, which prosecutors can treat as transport or distribution instead of simple possession.
TSA states that its officers do not search for marijuana or other drugs, and that screening targets weapons and explosives. In practice, a small sealed amount often passes through. The exposure begins when a substance is seen, smelled, or flagged: screeners are directed to refer the matter to a law enforcement officer at the airport. That officer applies state and local law, and the outcome ranges from confiscation to a citation to an arrest. Flower, edibles, and vape carts all appear as dense organic material on an X-ray and can trigger a bag check. Some airports in legal states even place amnesty boxes before the checkpoint so travelers can discard cannabis on the way in.
Use case: there is no route where this is authorized. The lowest-exposure version is a tiny personal amount on a nonstop flight between two legal states, and even that carries federal risk.
Traveling With Cannabis in a Car: How to Store It
Use case: none. Checking the bag adds delay and paperwork without removing the federal problem.
Use case: not a workaround for travelers. Whether a licensed retailer can ship to your address is a separate question that turns on state law and the carrier's own policy.
Use case: driving is lower risk than flying only in the sense that no screening is guaranteed. It does not make the trip lawful.
Use case: this is the option that keeps the trip clean. Buy what you plan to consume, and leave the rest behind.
The 2018 Farm Bill removed hemp, defined as cannabis with no more than 0.3 percent THC on a dry weight basis, from the Controlled Substances Act. TSA guidance reflects that and permits such products in carry-on and checked bags. The catch is proof. A label does not settle the question if a test or an officer says otherwise, and some hemp-derived items sold in smoke shops carry delta-8 or delta-9 THC above the federal limit. Keep packaging and receipts, since the traveler usually carries the burden of showing what the product is.
A state medical card protects you under that state's law and stops at the checkpoint. TSA guidance states that medical marijuana remains illegal under federal law and that officers will refer a discovered substance to local authorities. Do not expect a card, a dispensary receipt, or a doctor's recommendation to end a conversation with airport police.
Flying with weed across state lines is not a gray area in federal law, and the airport is the worst place to test the boundary between state programs and federal prohibition. Leave it at home, or buy from a licensed shop after you land and use it before you fly back.