Not a 121/135 guy, yet. However, I own my own plane in the NY area. Friend of mind who sometimes flies for an older and retired famous sports figure asks me if I'll give another "friend" of his a ride in my Cirrus. (At this point no idea who it is, etc. etc. etc. I don't even know it's a celebrity). Guy wants to experience GA and see if he would like to fly and own his own airplane. Sure dude I tell my friend but why don't you do it, he said won't be around.
So, I meet the "guy" at the FBO and though he looked somewhat familiar, I don't know him. However, I do notice there's a little commotion going on around the FBO. I'm oblivious to why. I take the guy to the airplane and the ritual begins, pre-flight, briefing, etc. etc. and the dude is engaged, asking questions and wanting to know stuff. He wants to learn to fly and in a Cirrus and I go, "well a Cessna 172 or Piper Warrior may be a bit cheaper." (this comes back to be embarrassing)
We fly around the NY area, his home in CT, the Hudson tour and are heading back to the airport when I ask him when he will train, where. "you know you should devote time and make it a priority." He giggles/laughs and and says, "well don't know if you recognize me, but I'm off about 4 months a year, I'll do it then." And how is that I ask and he tells me he plays pro xxxxx for a sport that I hate and don't watch and know little to anything about but apparently 90% of NY'ers do.
So we laugh and talk about it, and I tell him, tongue in cheek, I don't watch don't know much about it and if I did I'd be a fan for the cross town rival. Great convo about sports and flying on the way back and very cool dude. He offered to give me some cash for fuel and I said no thanks I love sharing aviation with folks.
As others have said here, just a normal guy. When we returned he was gracious with those at the FBO who wanted an autograph or selfie and he was on his way. About a week later I get a text from my friend saying there were 4 "player" tickets for me from the "guy" for an upcoming game, but I'm sure you don't want them so I'll take them. No way, I went to game and still hate the sport but I have a good story and someday can share the experience and real name!