To piggy back of Roverman's example, MAN benefits from being the primary (long haul at least) airport for a number of major cities, not just Manchester.
Leeds, Liverpool, Sheffield - and to a lesser extent Newcastle, Birmingham and the East Midlands. Each of these is at least as large as Lyon - and in some cases, significantly larger.
I still think MAN has a long way to go to reach its potential and act as the primary global gateway for the north of England and Scotland. Programmes like the TP, and surface access schemes (including HS2/3, TP Tunnel) will help MAN achieve this from a catchment perspective. However, getting the critical mass to achieve a strong transfer product (UK and European transfers) has to be on the agenda, and it is pleasing to hear that this is starting to bear fruit.