The fifth generation fighter F-35 (aka JSF) has successfully finished its first flight on 15th Dec 2006.
It houses the most powerful engine (Pratt & Whitney F135) ever used in a jet fighter - producing 40,000 pounds (177.9289 kN) of thrust.
The Joint Strike Fighter (JSF) is the most important fighter plane that the USAF (United States Air Force) plans to implement on its fleet. However its not the best. The F-22 Raptor has better features and combat ability. But it loses to the F-35 in its price tag.
While a F-35 costs $60 million, the F-22 costs $250 million. USAF has mentioned that the needs for the F-22 Raptor are limited as the country doesn't face the kind of threat that the F-22 is designed for.
Video : F-35 lighting II first flight
Official Web Site