We’re only 21 states away from being able to call America a weed-friendly country, since the first legal state Colorado in 2014. Since then, marijuana has also been legalized in Uruguay and Canada, where you can hold up to 30 grams (1 oz).

Nationally, weed is still illegal and so is traveling with it or other cannabis-related products, like oils, edibles, or hash, under federal law. It is not allowed during travel, depending on varied locations.

Here’s everything you need to know about traveling with marijuana.

1. You Can Be Stopped From Boarding Your Flight

If you appear to be high or under the influence prior to your flight, you may be prevented from boarding the plane. A Federal Aviation Administration spokesman said airlines have the right to refuse passengers who appear to be under the influence of drugs.

2. Check State And Federal Laws Before Traveling

Trying to take a little back home? You might want to check federal and state laws about size before doing so. Passengers older than 21 are allowed to travel through LAX and on flights with no more than 28.5 grams, or about an ounce, of marijuana and 8 grams of concentrated marijuana. You should be fine flying to other weed-friendly states, but don’t say I told you to try it.

3. Marijuana Is Prohibited At Denver International Airport

How sway? Passengers are expected to discard their remaining stash before heading to the airport. It’s unlawful to “sell, display, or advertise any product bearing the image, likeness, description, or name of marijuana or marijuana-themed paraphernalia or related business, according to Fly Denver.  

4. International Travel Is A Bit Tricky

My advice: don’t do it. Don’t run the risk of possibly going to jail in another country. In South Korea and Japan, possession or use of marijuana can result in a stiff fine and even a few years in jail. Some countries also regulate their citizens even when they’re in another country. Citizens of Canada can be barred from the U.S. for life for admitting to smoking marijuana in the U.S.

5. TSA Is Looking For Marijuana

TSA officers are required to report any suspected violations of law, including possession of marijuana and cannabis-infused products to local police. “TSA’s screening procedures are focused on security and are designed to detect potential threats to aviation and passengers.” Once again, check state and federal laws before traveling across the state or country lines. If traveling with medical marijuana, keep your ID and prescription cards available at any time.