Unbeknownst to many travelers, the planes they fly on could be vehicles for human trafficking. Traffickers can hide in plain sight, as long as people don't know how to find them. The organization Airline Ambassadors is arming people with the knowledge to identify trafficking and intervene. Founder Nancy Rivard spent last week training flight attendants in Houston to prevent trafficking during the Super Bowl since it tends to increase during major events. She and her colleagues taught airline staff some of the most telltale signs, including people who look like they may be injured, drugged, or in distress. Also, someone who is speaking for their travel companion or acting defensive when they're spoken to could be a trafficker. A passenger who is dressed less well than their travel companion, who doesn't have basic information about their flight, or looks at someone else when they're asked a question should also get a closer look, according to CNN . Shelia Fedrick, an Alaska Airlines flight attendant, told NBC that she correctly identified a victim who "looked like she had been through pure hell" and was with an older man in nice clothing. She placed a note in the bathroom, and the girl wrote "I need help" on it, prompting the pilot to summon police to the terminal. Once people sense something is wrong, they're not supposed to intervene directly, since this could become dangerous. Instead, they should tell the pilot, like Fedrick did. Last year, U.S. Immigration and Customs Enforcement found 400 victims and arrested 2,000 traffickers. Airline Ambassadors is hoping for legislation to require all U.S. airline staff to be trained so that even more people can be helped. Spotting trafficking is important throughout the entire travel industry, not just on flights. Several airlines, hotels, and tourism companies have signed The Code of Conduct for the Protection of Children from Sexual Exploitation in Travel and Tourism , which says they'll teach their employees signs like the ones Airline Ambassadors uses. They'll also hold themselves accountable for reporting anything suspicious. Travelers can also make a difference by learning the signs of trafficking and reporting them to airline staff.