I cannot see what is wrong with a bus as long as it is reasonably new, easy to get luggage onto, warm and free. After all we are used to short hops on the bus - we park the car in Long Stay and jump on a bus, we hire a car and get bused to the parking lot, at larger airports such as Heathrow we await a hotel bus. At Gatwick you see people all day long transferring from the South terminal to North Terminal on the Shuttle train hauling bags and cases etc.