Federal flight regulations often pertain to what passengers are permitted to carry aboard an aircraft, whereas individual airlines regulate things such as clothing attire, body odor and the use of service animals. Among other regulations, federal guidelines mandate that passengers age 18 and older provide identification issued by the government prior to embarking on a flight and that cellphones are not used aboard an aircraft except in airplane mode.
While federal regulations specify that no firearms are allowed on an airplane, some are permitted to be checked in luggage, such as pellet and BB guns, starter pistols and replicas of real firearms. Passengers may check in flare guns so long as the gun is unloaded, carried in a hard-sided and locked container, following hazardous material guidelines, and declared to the airline prior to flight. Flares, gunpowder and gun lighters are not permitted in any circumstance.
American Airlines reserves the right to refuse to transport a passenger with an offensive body odor, while Air Canada removed a passenger in 2010 for his odor. San Francisco-based Virgin America regulates that passengers have clothing on their top and bottom, and Alaska Airlines specifies that a person's midriff may be exposed. Most airlines prohibit bare feet. On Delta Airlines, passengers may carry animal antlers, but the antlers must be free of residue, with the skull wrapped and protection on the tips.