I did the MSc in Air Transport Management few years ago at Cranfield (full time). Great course. However I am still not convinced this will help with a flying career... I am working as an F/O now (medium size UK airline) and unless you are very senior in a "major", I do not think it will make a diference. Take it as a (very) long term project.
Other views on this point from ex-Cranfield (ATM) students are very welcome!