Ally Minium
In the OAG - which has almost godlike status it says
Niederrhein - See Dusseldorf
Under Dusseldorf it says:
DUS Dusseldorf Rhein Ruhr
MGL Dusseldorf Moenchengladbach
NRN Dusseldorf Niederrhein
The whys and wherefores I do not know - but offically it is branded as a Dusseldorf airport.
Seems to me that for an average sized provincial city Dusseldorf has more than its share of airports.
