Try: http://www.tripcentral.ca offers packages to New Orleans

http://www.flyforless.ca/ Offers Westjet etc.

http://www.exitravel.com For US, only offers Florida and Nevada but covers a couple of charter airlines.

http://www.searstravel.ca Flight search allows you to restrict to charters, Westjet or Air Transat.

Of course, there is Travelocity.ca and Expedia.ca

I look online but I find that sometimes my travel agent gets me a better fare (consolidator or open jaw) and I am protected by consumer protection laws for the travel industry.

Frances Toronto, Canada