[leakinInTheBlueSea]

Telling Phoenix ATC that you want to hang out a bit to say hi to a friend isn’t something that normally happens. Why not? was probably parked on the south side of the airport where an FBO is located (as well as Swift Aviation, which provides the type of executive service to which you are referring). U.S. ATC is not like Europe... you do not have a departure slot that you lose by not showing up on time (except at LaGuardia I think). You file a flight plan and (assuming there are no issues with the flight plan) contact the tower when you are ready to depart... that is done AFTER the pre-flight checks, after fueling up, after the pax are on board and after the door closes. You do not contact the tower until you are ready for a taxi clearance to toward the runway.

[tcrlaf]

At most U.S. airports, you can move, taxi, or just sit in an aircraft all you want, as long as you don’t cross the zipper line.

[Celerity]

Ok, I wasn’t aware of the nuances of flight plans, expirations and etiquette. I thought everyone had to fall into their departure slots.