Twinact - 'RAF, AAC and FAA forums would seem to be the natural breakdown.' - now you are proposing not only that it is military aircrew, but only UK. nb the 'of the World' bit in the forum descriptor.
And as for access, I think it must be easier to regulate the airline forums, if only by staff number and posing some questions that only an insider could know, but how would this be done for a worldwide, military aircrew only forum?
sw