A more rationale assessment would be to look at net passenger growth across the airports in the North West and trade off declines at other airports vs growth at MAN.
Rolling Year to October 2012
Manchester +4.4% (+2.6% ATM)
Liverpool -13.3% (-19.8% ATM)
Blackpool -1.3% (+6.7% ATM)
Leeds Bradford +0.6% (-7.8% ATM)
East Midlands -2.6% (+1.8% ATM)
UK Average +0.8% (-0.7% ATM)
Make what you wish of these figures.