Thanks for your great question Elizabeth! You have so many options if you make the drive to Buffalo. We flew out of Syracuse this past September on Continental, and we both flew for less than the cost of one ticket from Ottawa. I've even considered making the five hour drive to Buffalo to take advantage of the great deals on
Southwest Airlines. If you sign up for the "Ding" fares from their homepage, you will get specials from Buffalo daily, and I've seen Orlando as low as $69 one way. Taxes on flights from the US are also a fraction of what we pay in Canada.
JetBlue also has great deals, so check their website often. In addition to those two, I check
Expedia to see fares from the major airlines. If I find a good one, I'll then go to that airline's site to see if they are offering it for less, which is often the case.
Please email back if you have any questions as you continue planning Elizabeth! Best of luck in getting a great deal on a flight!