I agree entirely. The currency of international travel is the city. Regions/counties or whatever you wish to call them are meaningless outside their own country. Just look at how many atlas pages show 'Yorkshire', 'Tuscany', 'Lower Saxony' etc.
The argument for a 'Yorkshire' airport also relies on an assumption that residents of the region will automatically flow to an airport located in the centre. I would argue this is flawed: those in the north will still consider Newcastle, those in the west Manchester and those in the south East Midlands, just as they do now.