It depends a ton on where and when. I had "The State of New York" as a client once, which required commuting from Maryland to Annapolis and staying for the week. It's about a 5 hour drive, vs a 1.5 hour flight, which seems like a slam dunk, but considering that the airport is a half hour away, and I had to arrive there an hour early for TSA, ride in a cramped plane with not enough leg room, then rent a car on the other end and drive a half an hour to the hotel, it was down to traffic to determine which method was faster re: total travel time.
I found the drive more relaxing, more comfortable, and since I'd need a car at the destination anyway, just about the same degree of practicality.
I basically determined then that 6 hours away was probably my breakeven point at which flying became obviously more practical, but even then it depends on the target airport, traffic, weather, etc.
I certainly don't blink at the prospect of flying from Maryland to San Francisco, and would almost never consider driving instead, but IMO it's hard to fault someone valuing their rights over their time that it downweights flying significantly more than it does in my rankings.
I should probably also factor in that our location affords us a great variety of places we can go by train, and anywhere obviously train-accessible usually makes that a strong option. New York makes almost zero sense to drive to, and while the big knock against trains are the cost, it works out when you consider the cost of parking in New York, and the convenience of showing up at the train station 5 minutes prior to departure.