Earlier today, Frontier Airlines announced that it had discounted its unlimited flight pass to only $399. The deal applies to the airline's GoWild! All-You-Can-Fly Summer Pass, which is Frontier's signature all-you-can-fly pass. This summer pass allows passengers to fly on unlimited flights for just one cent plus applicable fees, taxes, and charges. Travelers can take advantage of this deal for a limited time, but the flight pass lasts from May 1 through September 30.