Private carriers, such as airlines, are not subject to the constitutional requirements for searches that government agencies must meet. Airline personnel can search passengers without a warrant, probable cause or exigent circumstances. Furthermore, government agencies such as the Federal Aviation Administration (FAA) can make regulations that the airline must follow and that affect a citizen's guarantee against illegal searches and seizures.
Since the events of September 11, 2001, a number of regulations have gone into effect that require the "search and seizure" of certain passengers and their belongings. The courts have weighed a citizen's constitutional rights against the government's right to prevent harm and protect others, and the government has typically prevailed. Whether a certain act is an illegal search and/or seizure depends on the circumstances, but many of the acts discussed below have been held "reasonable" under past and current court decisions.
Do I have to show my identification to airline personnel?
Yes. Asking for identification does not violate the Constitution since you have the right to refuse, although you will not be permitted to fly. You can also be asked to present your airline ticket.
Can I be searched at an airport?
Yes, and generally you have consented to being searched at any airport by entering the screening area and going through the metal detector. The courts have held that the search of potential airline passengers is reasonable where the search is not more extensive than necessary, is made in good faith, i.e., searching for weapons, and can be avoided entirely by the passenger choosing not to fly.
My bag was picked for a random search, and I have refused to consent. I want to leave the airport but security is detaining me. Is this legal?
Yes. You have not been falsely "arrested" or imprisoned. Once you enter the airport screening area and begin to go through the security process you cannot suddenly decide to "revoke" your consent. You cannot decide not to fly after a certain security policy, such as a random bag check, has been triggered that is not to your liking.
TIP: By placing your bag on the x-ray screening conveyor belt, you have implicitly consented to a visual and limited hand search of your luggage.
Don't I have a right to travel, unhindered by government restrictions?
Yes. A constitutional right to travel about the country free from governmental interference does exist. However, by refusing to cooperate with airline security measures that consequently keep you from flying, your right to travel has not been violated. Other viable modes of transportation exist, such as driving or traveling by train.