There is a group that gets together every month or so at Nautilus Aquatics and hobbies on Quinpool Rd. Though invited regularly, I have never actually attended. I think it is mostly an imformal gathering of car modelers. If you are interested, stop in and ask Mike (the proprieter) about it. Tell him that you want to get on the email list. He sends out an email anytime a new kit (mostly cars) comes in, and any time a meeting comes up.
Although I haven't been to it in a few years, there is an annual model meet at the Halifax Fleet Club every winter, around April I think (ask around at the hobby shops). There are all types of models there, especially planes and naval subjects. IF the military or plane builders are getting together regularly, these guys would be the ones to ask.
The guys at Maritime Hobbies and Crafts (John or Mike) might know of some clubs in the area. I think there is a bunch of model builders that sort of hang out there on Saturday mornings. They might know something, also. This place is located across the street from the Halifax library.