Originally Posted by cova

TPA Airport Marriott is also in the terminal.

Monorail, right-in-terminal, etc. meet the requirement - same as a shuttle. The Monorail would be considered a form of shuttle. Use your feet to walk and you are shuttling. Using the word "shuttle" means that there is regular transportation to the airport - short of having to make your own arrangements (taxi or rental car).

To get back to the original example - the train from Manchester Piccadilly is 15 minutes via non-stop train for 4.10 GBP. That is actually cheaper and more convenient than getting from the Manchester Airport Marriott to the Manchester Airport. Maybe then all the Center City hotels in MAN would be more appropriate as an airport hotel than the Airport Marriott. The city of Manchester has 3 free "MetroShuttles" which circulate the city and the train stations.

The DoubleTree across from Piccadilly MAN train station is more convenient.

I still think the word "Airport" in the name implies some convenient transportation method. One can take a taxi or drive a car from any location to the airport.