This flight attendant had a gut feeling about human trafficking. So he followed it.

When three young women and a man boarded his flight, Wesley Hirata had a bad feeling.

The seasoned flight attendant, who has been with Hawaiian Airlines for the past 16 years, was concerned when he noticed an older man walking onto the plane with three young women. They didn't seem like they belonged together.

While this usually wouldn't be cause for concern — families come in all different shapes and sizes, after all — Hirata couldn't shake his instincts.

He talked to the group (though what he asked wasn't specified) and still had more questions. So he spoke to his fellow attendants, and they decided to check the manifest. What they found was shocking: All three women were traveling under the same name. One of them, reports stated, was visibly underage.

Hawaiian law enforcement met the plane when it touched down in Honolulu. After questioning, they labeled the situation as human trafficking and referred the case to the FBI. Airline officials and media at the time quickly reported Hirata had uncovered human trafficking for certain.  

As it turned out, the FBI's investigation determined human trafficking had not taken place, but they still praised Hirata's actions.

"We do appreciate Hawaiian Airlines employees for speaking out and saying something and bringing it to our attention," said Jason K. White, spokesman for the Honolulu FBI field office. "We encourage people to remember that if something seems strange or doesn't feel right most times something is wrong, however, that was not the case in this incident."

The FBI eventually confirmed the man was authorized to take the girls on vacation.

Flight attendants are trained to make these kinds of appropriate notifications with a specific aim to curb human trafficking.

In 2015, Congress made it mandatory for flight attendants to be trained in spotting human trafficking. Airline Ambassadors International — a nonprofit made up of airline employees who "travel to make a difference" — holds a yearly seminar on trafficking for flight personnel on an annual basis. And the Association of Flight Attendants, a union with over 50,000 members, has also made stopping the horrible crime of human trafficking an integral part of its mission.

Human trafficking is a global crisis we can all work to end.

According to UNICEF, there are approximately 21 million trafficked people all across the world. 5.5 million of those people are reported to be children. It's not just a crime; it's a business that brings in billions of dollars a year. And that means it's up to all of us to fight to stop it.

So what can you do if you're on a flight and are concerned that someone might be in trouble? "Trust your gut and prior experience [and] report the situation without alarming or confronting the passengers in a suspicious manner," Hirata told KITV 4.

Of course, that doesn't mean you can or should report everything you find suspicious — we've all got to think critically and everyone's got biases — but we should all keep an eye out for signs of trafficking in our communities.

Here's a list of signs to watch out for.

Correction 7/28/2018: A previous version of this story reported Hawaiian law enforcement had confirmed the case as human trafficking, per the airline and on-site media accounts. We have since updated this story to reflect the FBI's announcement.