That's very reasonable advice. I guess a flight it is. I feel like if there are minor issues when I arrive from a flight I'd feel tempted to pick up the car anyway, as annoyed and dissatisfied I would be - what a hassle to have to book a flight back empty handed and what a waste of money.
Tell the dealer what your plans are. When I grabbed my 991S, I bought it out of state. I told the dealer that I was coming to check the car out before having it shipped (I had already put a deposit down at this point).
I also talked directly to the GM and asked him very politely to have one of his sales reps go over the car with a fine-tooth comb and note/photo any imperfections on the car. I let him know that I would most likely overlook a few imperfections but if they failed to disclosed any cosmetic or mechanical issues, I would walk.
The dealer sent me a full video and pictures of (2) tiny rock chips on the hood. Upon arrival, the car was truly very close to perfect and the deal went smoothly. The price of the plane ticket was worth the anxiety I would have felt buying sight unseen (especially experiencing a prior issue) and waiting for the car to arrive in my driveway.
Personally, 1-1.5k miles would be too far of a drive for me. I would book a round trip and still have the car shipped back. Besides the distance, I would do this for a couple reasons:
1. If something is wrong with the car and it's "no-go", I wouldn't want any pressure to just settle and drive it home. Knowing you are taking the plane back either way can really help keep your mind clear.
2. God forbid something with the deal goes wrong and it takes a couple of days to sort out, you may not have the luxury of being stuck a couple 1000 miles away for a few days. I financed my wife's E-Class through our bank (Bank of America) and the Bank cut us a check for the car to give to the dealership. We had already seen the car and were all set to go pick it up. Mercedes wouldn't let us drive the car away until the check cleared... They claimed their insurance covered personal checks but not checks from an outside bank.... So I could have written a personal check and drove away but the check from BoA was no good. It was one of the most preposterous situations I have been in and if my wife wasn't in love with the car, I would have walked from the deal. I say all that to say a deal isn't done until you are driving away and a lot can go wrong and you don't want to get stuck or worse yet, be forced to take the car when something still needs to be done (e.g. service, detailing).
