The Lockheed Martin F-35 Joint Strike Fighter has returned to flight with a 55min test sortie on 7 December. And, just over an hour after the aircraft landed back on the Fort Worth, Texas runway, Lockheed launched the F-35 avionics testbed - the CATBird - on a 2h check flight. The first F-35, aircraft AA-1, last flew in May, when a brief electrical failure cut short the aircraft's 19th test sortie. The maiden flight was in December 2006. The 20th flight, flown by F-35 chief test pilot Jon Beesley, tested engine performance and aircraft handling qualities up to 20,000ft in...