United Airlines is rolling out a new offering at Denver International Airport designed to get Colorado visitors off their planes and into the mountains — or to Larimer County — ASAP. The mechanism: A bus. The carrier, the largest operator at DIA, announced Friday that it is partnering with ground transportation company Landline on a service that will allow passengers to get off their planes and board a bus from the airport’s Concourse A direct to Breckenridge or Loveland. No airport train to the terminal, waiting for bags at the carousel, taking a shuttle to a rental car office or hailing a cab, Lyft or Uber.