It looks like all the good city names have already been snapped up by other airports so the only option is to give Donny a regional name that might confuse foreigners enough to make them fly there. NORTH of ENGLAND INTERNATIONAL perhaps or how about NORTHERN COUNTIES INTERNATIONAL. They could have a dig at MAN and LBA and use TRANS-PENNINE INTERNATIONAL.
We are of course assuming that MOL is not going to jump in with his chequebook and get it named UNITED KINGDOM and NORTHERN IRELAND REGIONAL, INTERNATIONAL and INTERCONTINENTAL AIRPORT. That way he could market it as every city in the UK and that EU (drain on our country) lot could do nothing about it.