In my entire flight history, there’s only been one time I was 100% sure an air marshall was on my flight. Mostly because the air marshal identified himself during an altercation. (It sounds more exciting than it actually was).
However, there have been times when I strongly believed there was an air marshall on my flight. There are some signals that suggest that someone is an air marshal–signals that are not quite as telling as the air marshal literally announcing himself.
There was a whole thread of conversation on Quora about identifying air marshals.
1. A lot of people seem to know who he is
Is he getting a lot of slight head nods from the crew? Do they seem happy to see him? Chances are, he’s an air marshal, and they are glad to see him.
Of course, there’s also a chance he’s a very well-loved frequent flyer who they want to be very subtle about greeting, but those chances are lower.
2. She’s wearing clothing inappropriate for her destination
If she’s wearing a coat and headed to a warm, beach location, she’s probably not planning on spending that much time there.
Though, she could just really love that coat.
3. Start a disturbance and see who gets up to stop you
Here’s a sure-fire way to find out. Start making a disturbance and see if anyone else besides the crew gets up and runs after you shouting, “Stop! I’m an air marshal!”
Ultimately, if the air marshal is doing his job correctly, you shouldn’t be able to spot him on the plane. But the items above were ones identified by frequent flyers as key giveaways.