Senators probably don’t cross the threshold. You gotta have a lot of money and a lot of status with the airlines. Also likely not all airports will have/do this.
I also have a billionaire friend who only flies coach. Personally I think he’s a moron for doing so, but respect that he’s so cheap. You generally keep your wealth by being cheap, but realistically business versus coach won’t fundamentally change anything. It’s more the principal.
Fun anecdote: friend of mine's dad is a ~billionaire, and not only does he still fly commercial, he flies coach. And has family come pick him up from the airport. Epic tightwad. Never spends money unnecessarily. To his credit, he also works at the local soup kitchen once every week like clockwork. How he does that while maintaining a 90 hour a week schedule, I have no idea.