Primarily for general aviation discussion, but other aviation topics are also welcome.
My advice has just been asked by a former student of mine, who has just got a job teaching aeronautical engineering at a University in Belfast.

He's asked if I can suggest where he can take his students to expose them to some quality time around flying machines (when he was doing his PhD with me, he used to help me teach an aircraft design class, where I used to bus them out to Duxford).

I have been to NI only a handful of times, and never on a trip that involved aircraft museums. He'd never been there until his job interview!

Can any of you chaps make any useful suggestions I could pass on?

The Ulster Aviation Society isn't "officially" open to the public but might be persuaded for educational group visits.
There are some interesting aviation exhibits in the Ulster Transport Museum at Cultra (on the Belfast to Bangor road) including the SC1 VTOL, a replica Ferguson monoplane and some other bits & bobs. On my last visit they allowed me access to view the (dismantled) Shorts Sealand currently in storage.
Some basic info here