Dan wrote, " Where do you get this information? The highest fare between Toronto and Chicago is over $900."

Dan,
On March 1, I checked the price for a Toronto - Chicago flight at href="http://www.flyporter.com/fly/Search.aspx?culture=en-CA" target="_blank">www.flyporter.com/fly/Search.aspx?culture=en-CA
by checking the One way button, clicking on Toronto for 'Leaving from' and Chicago for 'Going to' and entering the promo code that was valid on that day and that appeared on the same website.
The figure that the Porter website calculated was $191.20 after the discount - their figure, not mine.
This is the amount, $191.20, that the airline gets. The taxes, etc. do not go to Porter, so I left them out. They do not figure in Porter's revenue stream.
I used a one-way fare to simplify the math. A return fare calculation would double Porter's revenue but it would also double the costs supplied by Bombardier.
I hope this helps.

Bob Kotyk