Got this deal from my Hertz monthly statement.
"Fly Midwest Airlines on your next trip and save 15% on tickets with a minimum fare of $275 to any of the airline's destinations coast to coast. Enjoy the onboard comfort and outstanding service that have earned Midwest the reputation for providing "The best care in the air.®" Book your tickets online at midwestairlines.com by August 15, 2008, using promo code HERTZ15. "
the link is here
I personally do fly them, but maybe useful for someone, you can accumulate Northwest Airline miles