I wouldn't be surprised if AllegiantAir have some sort of exclusivity deal with OGS since they subsidized the airport expansion.
As far as prices for flights from Ottawa (or Montreal) being lower, I haven't seen it (Direct flight from YOW or YUL to MCO for Dec 24 2016 to Jan 7 2017 are roughly $1100CND plus baggage fees per person (that's about 50% more than the $3k you listed for 4). AllegiantAir is around $450US plus luggage fees).
So I went back and checked my booking -it was March 2014 (left March 3rd so before March break price increases) and in fact the price I recall with Air Canada must have been for 3 people (not 4) as we had a 2 yr old at the time and only bought 3 tickets with JetBlue. To do a direct comparison I arbitrarily chose early March 2017 and for 3 tickets with weekday departures it comes to 654 pp all in return (not including luggage) so lets say $700 pp x 3 = $2100 total to go direct with AC this upcoming March (vs over $3000 March 2014 ). So there is some saving to be had - I think it can come down more.
It will be interesting to see how long the exclusivity with Allegiant is for - you're right that they helped foot the bill and will not roll over unless they have to
As far as prices for flights from Ottawa (or Montreal) being lower, I haven't seen it (Direct flight from YOW or YUL to MCO for Dec 24 2016 to Jan 7 2017 are roughly $1100CND plus baggage fees per person (that's about 50% more than the $3k you listed for 4). AllegiantAir is around $450US plus luggage fees).
So I went back and checked my booking -it was March 2014 (left March 3rd so before March break price increases) and in fact the price I recall with Air Canada must have been for 3 people (not 4) as we had a 2 yr old at the time and only bought 3 tickets with JetBlue. To do a direct comparison I arbitrarily chose early March 2017 and for 3 tickets with weekday departures it comes to 654 pp all in return (not including luggage) so lets say $700 pp x 3 = $2100 total to go direct with AC this upcoming March (vs over $3000 March 2014 ). So there is some saving to be had - I think it can come down more.
It will be interesting to see how long the exclusivity with Allegiant is for - you're right that they helped foot the bill and will not roll over unless they have to