Do not worry about falling passenger numbers on various routes from this North West owned airport. This airport will be kept open. Routes will continually make a comeback.
Far far less than ideal Yeadon verses far far less than ideal Finningley is propelling the whole North West of England and Manchester Airport especially.
Having ONE well located [allied to greatest potential population catchment], connected and in time fully functioning airport within the Yorkshire and Humber region (aiding the whole North East of England and North Midlands) would completely change the face of civil aviation in the North West of England.
The irony is that both Doncaster and Leeds economy would go through the roof with the scenario above rather than the utter failure and exporting of wealth to immediate neighbours that is now the historic norm.