OK the question is about smaller airports, but here's my growth analysis at several Canadian airports of various sizes that I see as having good potential:
YXX Abbotsford was started by WJ and now has C3 as well. Always good to see communities without previous service getting flights, as previously people drove either to YVR or all the way to their destination. YXX is a very nice alternative for people living in Abbotsford, and there is some market yet to grow there.
YYC Calgary is going to have a bit of a reduction in capacity and in connecting traffic due to AC/CP consolidation, but where I see good prospects is in the new agreement over Japan and Hong Kong treaties, so maybe a charter airline could look at flying YYC-Asia to cash in on the demand for that service, especially due to YYC's proximity to Banff National Park.
YEG Edmonton probably won't see too much in the way of capacity growth, but is seeing new routes developed as a result of AC/CP combining, routes which are long overdue. Now hopefully we will see a few remaining holes in the regional network filled in. Also, I am upbeat about the YEG terminal expansion. While I don't find the YEG terminal particularly beautiful, and I'm not sure it would be my choice of design to base an expansion from, it will at least grow in size and be a reasonable facility when its finished. The expansion should, I hope, attract at least one new airline to YEG from the US, which I feel is needed.
YQL Lethbridge currently has some turboprop service to Calgary and some King Air flights to Edmonton, but that's about it. There is, however, a large number of people who drive to Calgary to fly from. For an airline like WestJet to come in with east-west routes would be a very good thing, and I am confident it would be successful.
YBR Brandon was subject to some limited edition trial flights by WJ last year, and back in the old days had a YYC-YBR-YYZ route on Pacific Western which was quite successful. WJ returning for another limited edition summer service or permanently would, I think, have good potential, although WJ's focus right now is obviously on the eastern network. YBR is also currently served by Perimeter Airlines and Athabaska Airways to YWG and YQR, but these airlines are really commuter hops so connecting traffic is very minimal if any, so I don't think WJ would hurt either of their operations, either.
YWG It's a shame for Winnipeg that Greyhound was bought out for the non-airline part of the company, because I feel that idea had some real potential (and I believe still does if fixed up for the current market). Despite that setback, however, the last few years have given strong growth at YWG, and I believe more is to come. For one thing, WJ's move east means that YWG will no longer be at the fringe of their service area, so they have tremendous expansion potential. In addition to a significant market waiting to be stimulated by WJ, there was a previous state of insufficient capacity, so YWG is doubly set for new service. Unlike YEG, however, I feel that new service will be capacity increases without new routes, as potential for growth is largely on existing routes. New routes and new airlines will probably take a while to develop while most expansion will be to destinations or alternate airports to destinations which are already served. Perhaps by the time the new terminal building is ready it will make other airlines really want to come in (architecturally YWG is my favourite terminal however, I love that style, so it will be sad to see it replaced even though it is quite crammed at peak hours right now). (Also, FYI the reason the airport hotel is so short is because it's close to the control tower, but there is a second brand new hotel just outside of the airport premesis that just opened this month, too).
Toronto YYZ is big enough to create traffic for itself as a hub, and for new airlines to want to serve it-enough said. Toronto Island Airport YTZ, even without RJ's, has some potential for growth with turboprops if Air Montreal, for instance, was to fly there.
YHM Hamilton is another market that was not served. Even if YHM doesn't get traffic from closer to Toronto, there is enough of a market locally to stimulate growth for quite a while. I feel that although YHM is unlikely to become a business traveller's airport, it also has good potential for charter flights to come to it now that WJ is out and raising its profile, so that YHM is actually an alternative Hamiltonians will consider using.
Windsor currently is mostly turboprop traffic to YYZ, but based on the area population there should be more than enough local demand for east-west flights. This is a very good market for an airline to begin serving, in my view, as is London, Ontario which is in a similar position.
YHU St. Hubert is currently used as a general aviation airport for Montreal, but can accomodate larger jets. It's lack of congestion, good proximity to target markets, and lower costs compared to Dorval all make it fairly attractive, again just in my view, for an airline wishing to begin service. It's chief disadvantage is the lack of a proper terminal, but that didn't stop WJ from building one at YXX, so why not at YHU as well?
YUL Montreal Dorval has lagged years behind in growth, and has some catching up to do. With the reconsolidation of flights to YUL from Mirabel, it is looking up for YUL's potential as a hub, but there's a big if, which is if YUL manages to get the needed terminal renovation and expansion. Indications are, however, currently that YUL will indeed be able to grow as a secondary hub within the AC/CP network and should also now be in the process of becoming a more attractive airport to US carriers as well, as YUL's North American route network in particular has been in pretty poor condition.
YHZ Halifax could possibly suffer a little from the changes brought about by the AC/CP joining forces as YHZ could loose a little bit of connecting traffic, but local traffic growth MAY have the potential to give YHZ a decent growth rate. In developing it as a hub, however, I believe there are two factors that may make or break YHZ. One is that it needs a flight to FRA to provide Star Alliance connections with AC. Secondly, YHZ needs US customs pre-clearance facilities, as it is the only one of Canada's 8 class I airports without them. With pre-clearance the increasing of RJ use may continue the development of trans-border routes hubbed through YHZ. Without pre-clearance it may make more sense to just add US flights to other maritime airports, as they would essentially be on equal footing with YHZ with regard to customs facilities.
YYT St. John's is far out on the east coast, and as such cannot offer the same transcon routes as more central airports, so I doubt YYT will be getting non-stops to anywhere west of YYZ in the near future. The addition of a YUL non-stop, however, is a good thing, and certainly growth is possible based on the economic upswing in the area. What YYT really needs is WJ service to link it to all of the Newfoundlanders who have moved west in the past tough economic times, as low cost service would stimulate travel to and from Newfoundland quite well. The other thing YYT needs is for a US airline or for AC/CP to take advantage of the RJ's capabilities, and fly from YYT to the US non-stop. A simple BOS flight would make YYT better, but given that St. John's isn't a huge city it may take quite a bit of time to develop the service.