AURORA, Colo.--Flights by Nellis AFB, Nevada's Experimental Operations Unit (EOU) for Collaborative Combat Aircraft (CCA) are to lead to requirements for Increment 2 of the CCA program, a U.S. Air Force acquisition official told reporters here on Feb. 25 at the Air & Space Forces Association's annual warfare symposium. The Air Force has said that there are nine vendors for Increment 2, but the service has not identified the companies. The General Atomics' YFQ-42A Dark Merlin CCA prototype is competing…