(CNN) Decades after the U.S. Air Force unveiled one if its first stealth combat planes, the B-2 bomber, lawyers are still arguing over the origins and legal ownership of the technology that allows pilots to fly virtually undetected by enemy radar. On February 19, a federal appeals court ordered a hearing to determine whether the Pentagon infringed on a patent owned by Zoltek, a materials company from St. Louis, when it developed the stealthy coating for the F-22 fighter plane and B-2 bomber. In the latest development in a case that has spanned nearly 20 years, the ruling reversed a Federal Claims Court judge's 2014 decision that sided with the U.S. government by determining that Zoltek's patent was invalid.Lawyers are still arguing over the origins of stealth technology used on two U.S. military aircraftCourt ordered hearing to determine whether the Pentagon infringed on a patent owned by ZoltekZoltek was granted a patent in 1988 for a method of making products more resistant to electricity
Among those decisions was one that determined that Lockheed Martin, the manufacturer of the _, would not be included in the legal proceedings.