Although marijuana is legal only in some states, and for medicinal purposes in more, pot remains illegal under federal law (but where it’s legal there are even loyalty programs with reefer-a-friend bonuses). You have to clear a federal checkpoint to fly commercial. And the TSA (T)akes (S)tinkweed (A)way.
Colorado Springs airport installed amnesty boxes so that passengers could leave their weed rather than break the law. This is, in essence, free pot for airport employees. And the practice has spread to the Aspen airport where they offer Pot Only waste bins.