Just had a thought could it be the name is why the airfield will not sell.
Kidlington has done it to London Oxford. I think London Coventy does not have a good ring to it.
What about Birmingham Terminal 3. I am all for it. Copy the M4 near Heathrow and make one lane of the A45 a bus lane. Therefore passengers can check in at Birmingham then a good bus run down the A45 bus lane to Terminal 3.
Bonus would be Birmingham gets instant second runway.