ZIVKO AERONAUTICS INC
Founded in 1987, Zivko manufactures the Edge 540 series of aerobatic monoplanes from a 1,858 m² (20,000 sq ft) factory on the airport at Guthrie. In August 2000, it received FAA certification under Pt 21.191 (g). The improved Edge 540A was introduced in April 2001. In mid-2002 the workforce numbered 20.