I like how people have gotten caught up in the "technical" defintion of what doxxing is, in an attempt to justify it as doxxing. The real argument should be, does tracking Elon's jet actually put him in danger?
The answer is NO. Absolutely not.
With a private jet, you deplane in an area where people normally are not allowed to go. And especially for Elmo, he's likely deplaning with his security detail and getting straight into his car. Add on top of that Airports have some of the highest security of any locations in the nation.
So no, nobody is going to find Elmo because of his jet info. Anyone who thinks posting his flight info on twitter presents a danger is absolutely fucking stupid. If someone really wanted to hunt down Elmo, they'd go find his jet info from another source and then figure out how to get guns through the security of that airport, figure out how to unlock the doors to get on the tarmac, etc.
Elmo is either paranoid, or he's embarassed by just how much he uses his own private jet to get around after CLAIMING he's for the environment.