I may be naive, but it seems a flight attendant or pilot could have Googled the man, seen his profession, and left it at that.
My g/f lived next to an apartment with 4 Arabic men, who were part of the 9/11 pilots. After the attack, she was interviewed by the FBI. She had been suspicious of this group for months, but never said anything. She felt so bad afterwards.
So report, and hope that those people have some common sense.