Private flights also go where you need to. Not a big deal if you are headquartered in a hub and have business at a different hub, but as you have business in distance places a private plane ends up a lot faster because you don't have to wait in hub airports. I know my company keeps a flight crew in Frankfort Germany so that the CEO on trips from US to India they can land, refuel and change pilots and be off in 15 minutes. (I'm not clear if the crew lives there, or just flys commercial the day before) Though if supersonic airplanes were affordable I believe the CEO makes the US-Asia trip often enough to buy one.