On New Year's Day, the sale of marijuana for recreational became legal in California, the country's most populous state. What does that mean for air travelers who try to bring small amounts of marijuana with them? That is a conundrum for the state's airports, which are locally owned and operated but are subject to federal law, under which marijuana is an illegal substance. Areas beyond security checkpoints are under federal control. "It's going to be a very gray area," said officer Rob Pedregon, a spokesman for the police force at Los Angeles International Airport, the nation's second busiest airport. "We're still in the state of California," he said. "Open that [airplane] door on the other end" and passengers are subject to a whole different set of local laws. The Transportation Security Administration, the federal agency in charge of screening passengers, isn't specifically looking for drugs that are illegal under federal law, a spokesman said. Agents are on the lookout for weapons and explosives, however. But if TSA agents do spot pot in traveler bags, "law enforcement takes it from there and TSA has nothing to do with happens after," said TSA spokesman Mike England.

What happens? Nothing ... probably

"We're really not in a place to do anything," said Sgt. Ray Kelly of the sheriff's office in Alameda County, California, where Oakland International Airport is located. Travelers may be asked to dispose of their weed or edibles, if they are detected, before passing through security, but under the California law individuals can have less than an ounce of marijuana on them. "If the TSA says we don't want it [to get into the airport], we would have to intervene," Kelly said, adding that the county's law enforcement is more concerned by children who may accidentally eat marijuana candy or drivers who are impaired from marijuana use. Kelly said that procedures won't be too different under the new law because the state, like more than two dozen others, had already legalized medical marijuana. Other airports in states where marijuana's recreational use is legal have taken steps to allow travelers to ditch their stash before boarding. Colorado Springs, Colorado, for example, has an "amnesty box" where fliers can throw their weed away before passing through security. Pot is banned from Denver International Airport and officials ask passengers to throw their stash in a trash can, said spokesman Heath Montgomery. He said others don't try to retrieve it. "People don't go digging through the trash at an airport," he said. "It looks suspicious."

Can passengers board under the influence?

Before travelers consider giving new meaning to "red-eye flight," note that airlines reserve the right to turn passengers away if they appear intoxicated, just as they do if they are acting violently, yelling, or appear ill. "We're not going to let a passenger who's not fit to fly on an aircraft," said American Airlines spokesman Ross Feinstein. Smoking pot in an airport is prohibited as smoking in general is banned there. Smoking on planes in the U.S. has been banned for nearly two decades.

International travelers, beware