Cranfield do an
MSc Air Transport Management
The entry requirements are:
Applicants with other academic or professional qualifications are considered on the basis of those qualifications and any relevant work experience.
All entrants will be expected to demonstrate a keen interest in air transport.
Apparently an ATPL is regarded being sufficent. I could be wrong, but if you are really interested you could always get in touch with them to find out more.
They also have an
Executive MSc in Air Transport Management which is a part time course spread over 3 years with a number of one week residential professional short courses.