NetJets paid a bunch of $$$ to lobbyist and got an age 70 mandatory retirement bill for Part 91K and 135 operators over a certain number of operations pushed thru Congress. I think only NetJets and Flexjet are big enough to implement it. NetJets did it back in January so as of next January a few hundred geezers will be leaving NetJets. The owners were uncomfortable with pilots pushing 80 flying their jets.