Metrolink finally being under construction to the airport will help, especially on the worker front. For some reason people who dont "do" public transport are more than happy to use a tram.
To seriously improve the numbers there are a number of things TfGM could do:
1. West Coast Mainline - there was an
interesting article a few months back that Piccadilly is struggling to find capacity for more West Coast Mainline Trains to London. As some of these use the Wilmslow route why not start/end one an hour at the airport instead? (This could be extended to Cross Country trains / Arriva Wales etc who start at Piccadilly but go through Wilmslow, and make use of the facility to its best possible advantage).
2. Sell "Manchester Express" tickets at the airport, online and onboard as happens with STN/LGW etc? (I know you CAN buy online and they do have ticket machines in arrivals etc but would help airline retail sales and improve visibility).
3. (Slightly more off the wall) Get airlines to sell through tickets to Liverpool, Newcastle, Edinburgh etc i.e. flight plus train included, removes a level of stress from visitors and promotes "seamless" travel.
4. Get the Station Check-In working, one of the big barriers to travelling by coach and train I hear is that people dont want to be "lugging bags" all over the place. There are check-in desks in the station, use them and possibly later expand this to Piccadilly too.
5. HS2 Longer term this may
as the article says deliver many of the benefits but will be after BHX get HS2 so may put MAN at a disadvantage.