The Saab JAS 39 Gripen (English: "griffin") is a light single-engine multirole fighter aircraft manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force (Flygvapnet). The Gripen has a delta wing and canard configuration with relaxed stability design and fly-by-wire flight controls. It is powered by the Volvo RM12, and has a top speed of Mach 2. Later aircraft are modified for NATO interoperability standards and to undertake in-flight refuelling.