If you see someone on a plane or at the airport who displays any of these warning signs, alert a flight attendant or security officer. As a last resort, take things into your own hands.

Instructions

• TIP: Tell a flight attendant if anything seems amiss in the lavatory. Improvised explosive devices and weapons can be stashed there.
• Step 1: If you see someone who appears to be trying to light something, or you notice signs of smoke or fire, don't wait for someone else to react – subdue the person as quickly as possible and yell for a flight attendant.
• FACT: In 2007, the Transportation Security Administration spent nearly $1 million teaching airport security inspectors the program SPOT – Screening of Passengers by Observation Techniques.
• Step 2: Know the signs that someone has recently handled explosives, like chemical odors, stains, or burns.
• Step 3: Heed odd eye movement, like irregular glances from side to side or a refusal to meet people's eyes.
• Step 4: Make a mental note if someone is wearing oversize clothing, or dressing too warmly for the weather.
• Step 5: Pick up on questionable hand movements, like people who repeatedly check themselves, keep their hands in their pockets, or appear to be trading hand signals with other passengers.
• TIP: Security personnel are trained to be on the lookout for people who continually pat their chest – a sign that a bomb could be strapped under their jacket.
• Step 6: Learn some behavioral warning signs: Sweating profusely when it's not hot, walking awkwardly, staring blankly, and mumbling to oneself.