Today only, Frontier Airlines via ShermansTravel takes 50% off select nationwide fares via coupon code "BOOKNOW". (It's valid on flights on Mondays and Thursdays; the same coupon takes 30% off flights on Tuesdays and Wednesdays. Discount is applied to the base fare only.) Some exclusions and blackout dates apply. Shop Now Tips On the ShermansTravel landing page, click "FlyFrontier.com" in the top paragraph to see this sale.