The F-35 Lightning II fleet recently surpassed 15,000 flight hours, with operational F-35s accounting for more than half of the total. As of 7 April 2014, US Air Force, Marine Corps, Navy, and international pilots flying operational F-35 aircraft have flown 8,050 hours. Test pilots in the System Development and Demonstration F-35s have accumulated 7,123 flight hours. In 2014, test F-35As have been flown 328 hours; test F-35Bs have accumulated 191 hours; and test F-35C have been airborne for ninety-one hours. Pilots in operational F-35As have flown 963 hours, while their F-35B and F-35C counterparts have accumulated 1,012 and ninety-eight hours respectively. Recently, a total of sixty F-35 sorties were flown in one day at the seven F-35 bases.
