Let the Denver airline wars continue. As we predicted last week, both United and Frontier have matched (and in United, case, upped) the offer that Southwest initiated.
Southwest is offering a free ticket for each ticket purchased. United is similarly offering Colorado residents who purchase a ticket by February 14th a free additional ticket to any North American destination. For customers who purchase a ticket to a trans-Atlantic/Pacific or South American destination, United will offer a ticket anywhere in the world United flies.
Clearly, United is looking to leverage their global heft in the "Denver Wars" - clearly a free ticket to Sydney or Cancun is a lot more exciting than Amarillo. (No offense to Amarillo, of course.)