Dave Siegel took the chief executive officer role in January 2012. Siegel's tenure ran through May 2015, when he left for personal reasons and was succeeded by the company's chairman, Bill Franke, who would manage strategy and finances. In April 2014, Barry L. Biffle was appointed as the company's president, reporting to Siegel; after Siegel's departure, Biffle was charged with managing the company's day-to-day operations.
The initial JetExpress partnership with Mesa ended in January 2004, when Horizon Air was selected to operate the routes. Horizon utilized slightly larger CRJ-700 regional jet aircraft on these routes. In August 2006, Frontier and Horizon ended their partnership. While Frontier was generally pleased with Horizon's operation, the carrier decided that it needed to revisit the agreement and find a provider with additional regional jets to grow the operation. The last of the CRJ-700's was returned to the Horizon Air fleet on November 30, 2007.