Hi Vulcan,
There are two things you have to take into account here...
Money & permission
If I remember correctly from last year the Air Corps were allowed to attend 10 overseas events, possibly even less.
The Air Corps get numerous invites for events every year and they can only accept so many invites.
On top of that the Department of Defence has final say on participation and politics can always play a part.
All I'm trying to say is that it may not be an Air Corps decision, it could be money but it could also be politics.
Regards,
Frank.