As reported here, Frontier and United are engaged in a frequent flyer mile battle for travelers flying to and from Colorado through the end of September.
Frontier—which is based in Denver—and United—which operates a hub at Denver—are both offering double miles for flights to Aspen, Colorado Springs, Durango, Grand Junction, and, of course, Denver. The Frontier bonus is limited to flights into the five cities; United is awarding extra miles for flights to or from Colorado.
The bonus-mile promotions must be having a measurable effect on travel because Southwest—which is also a major player in Denver—has launched its own bonus campaign, clearly in response to Frontier and United's.
Southwest is offering members of its Rapid Rewards program one bonus credit for every one-way flight to or from Denver, through September 30.
In my original write-up of the Frontier-United offers, I surmised that Frontier probably regretted launching its promotion, which had precipitated an outsized response from United. With yet another aggressive competitor drawn into the fray, the intensity of Frontier's hand-wringing can only have escalated.
Travelers, on the other hand, can thank Frontier for stirring the sleeping giants, in the process making Colorado a richer place to fly, mileage-wise.