May we use The Public Service Alliance of Canada (PSAC) as an example? I understand they are "civvies", not CAF.
"Many of PSAC’s 172,000 members work for the federal public service, crown corporations or agencies as immigration officers, fisheries officers, food inspectors, customs officers, national defence civilian employees, and the like. However, an increasing number of PSAC members work in non-federal sectors: in women’s shelters, universities, security agencies and casinos. In Northern Canada, PSAC represents most unionized workers employed in the Yukon, Nunavut and the Northwest Territories."
http://psacunion.ca/
This may, or may not, be of interest to the discussion of unions,
The Mounted Police Professional Association of Canada is comprised of regular members of the Royal Canadian Mounted Police.
http://mppac.ca/
Would a ( hypothetical, of course ) CAF union represent reserve members?
As always, not to say a union is a good, or bad, thing for the CAF and its members.