“If I see someone who is muscular, powerful, strong, physically fit, I memorise his/her face and make a mental note of where they are sitting,” wrote Bridger on US knowledge-sharing site Quora.
Should an emergency occur, crew may well call on these travellers to help them out.
“I consider this person a resource for me. In the event of an attack on the flight or on me, these are my ‘go-to’ people,” Bridger explained.
“If a situation looks like it could develop, I’ll privately and discreetly ask one of these people if they would be willing to help us if necessary.