Bald guy is definitely secret service to Don Jr. They are both pictured together often. It is NOT fake arm guy. I also do not believe SR would be flying commercial flights with Don Jr. Especially with Mueller sitting in same terminal.

https://www.nytimes.com/2017/09/18/us/politics/donald-trump-jr-secret-service.html

Interesting article. If Don Jr. "gave up" SS detail. Why does he still have POBM (Pissed Off Bald Man) with him?

DIG DIG DIG