It's not a case that "NCL" and "MAN" people are against then there's something in these proposals. Again....
Who is going to pay for your vanity project? Show us the numbers. And factor in that the passengers that you expect to "boycott" Manchester will have to pay increased fares through airport handling/landing charges that will be high and passed on by airlines/tour operators to let whichever company developed Church Fenton get a return on their money. So basically you can rule Ryanair out as a source of passengers given theie history at other airports, and they are the airline most likely to provide a broader range of services than any other airline.
Low cost airlines WILL NOT flock to an airport that has much higher handling/airport charges than near by airport. The clue is in that label: LOW COST.
If you expect a host of Yorkshire councils to come together to spend money a building 1 airport and paying compensation to the owners of LBA, HUY and DSA instead of spending money on things of greater consequence i.e. local amenities and services at a time when funding from central government is being reduced, then that is being slightly naive.