We stick to flying out of Ottawa on WestJet. DH is deadset against flying any US airlines and Air Canada is too risky lately.
We have flown out of Ottawa, Toronto and Montreal and have just found paying the extra to fly out of Ottawa is easier and more convenient than driving somewhere and flying or taking multiple modes of transportation. Some people can handle it but we like to keep it simple.
As a PP stated, the fares aren't all that different. There is a difference when you cross the border (Syracuse, Buffalo, etc.) but if you can find a seat sale on WJ it won't be that far off!
I'm exactly the same. I love in winter when you have the direct fight with WestJet:
1 - WestJet is not likely to be on or threaten to be on strike
2 - WestJet employees make eye contact with customers and even smile from time to time - how refreshing!
3 - Doing the customs sprint in Toronto or Montreal is no fun, especially on the the way home
4 - With the direct flight, you only have to worry about the weather in two places
5 - WestJet reward program - you get WJ dollars and just use them against the cost of any flight you book, no black out periods, etc - there's a promotion to get a free companion flight when you sign up.
Love that feeling of slapping the DME tags on your luggage, clearing customs in Ottawa, and putting your brain in vacation mode, knowing that Disney will do all your thinking for you for the next week
The only downside (depending on your POV) - the flight leaves at 4:35pm, so you don't get to your resort until 9 or so. But the return flight leaves late in the day, so you can spend the full day in the parks. That may change from year to year.
[I'm not a WestJet employee BTW, just been burned one too many times by the other airline.]