Denver (tca/dpa) — Frontier Airlines is offering an all-you-can-fly summer pass for $399 for a limited time, the Denver-based carrier announced in February. The “Go Wild!” pass offers access to all of Frontier’s US and international destinations, which include New York, Los Angeles, Atlanda, Chicago, Ontario and Portland, from May 1 to September 30. The promotion applies to destinations across the continental US, Puerto Rico, the Caribbean and Latin America, said James Fenner, Frontier Airlines’