Someone mentioned Bradford to Manchester Airport services - there's no requirement as Bradford already has direct access to an international airport by the way of Yeadon Airstrip otherwise known as Leeds Bradford International Airport.

Sarcasm, I assume? Both on the suggestion it must be equivalent as an 'international airport' to Manchester, and also on the 'direct access' which, while technically true, is still, erm, limited, to put it politely.
I must have sold hundreds of tickets from Bradford Interchange to Manchester Airport, generally TPE Advances changing at Leeds or, if the times suited, via Huddersfield. I think there were some cheap Northern Advances too via the Calder Valley, but unsurprisingly they had few takers given the changes involved.
For my final year I was - in good faith - promising the direct Northern Connect service sometime in the future. In the meantime we had the odd extension of Calder Valley trains to Oxford Road, which generally just caused confusion and also managed to not connect with CLC services in either direction!
Presently, from home in Todmorden, a direct Manchester Airport service would obviously be nice, but there is a good connection into TPE at Victoria, and likewise to Liverpool. Calder Valley to Chester works well IMV, as there is no other train from Victoria, although of course if the Calder Valley to Manchester Airport option had been chosen it would have been possible to change at Oxford Road onto the TfW service to Chester and North Wales.