It's actually quite involved, they don't just accept the PDI from the builder and go pick it up or have it dropped off.
BA sends a quality crew to inspect every single part of the aircraft, they check all the records, the wiring, they look for build issues, are the seat cushions installed right, how about the seat belts, do the water heaters work in the galley, how about the microwaves, they check the entertainment systems, flush the toilets, and on and on and on.
Once all the problems have been ironed out, and they always find plenty of those, then it's time for flight tests before they finally sign for the aircraft. At that point it's their problem to fly it home.
Even in the military it can be like this. At RAE(Bedford) when we got our first Panavia Tornado we sent the maintenance crew and the test pilots to pick it up, they came back empty handed a few times before British Aerospace had everything to their liking.
The individual airlines have their own flight crew fly the plane to it's destination. The manufacturer's have crews that test the planes prior to delivery.
airlines' own pilots fly the plane back
Depends some airlines send up a whole crew and csr reps if it is a new plane to the fleet,, sometimes boeing delivers them.
A flight captain from the airline flies it back
The aircraft mechanics
Hopefully not these retards. Plane never even made it to the customer.
The airline has to pay for the airplane before they can take delivery. Once it belongs to the airline, the manufacturer's pilots are done- so the airline's pilots fly it away.
one of their heroes,,,, can guarantee that rarely it is not someone's pet do-gooder!