airspeed of the aircraft below stall speed before the drogue could be jettisoned (see Hawker Henley). Post-War The use of such aircraft continued post-war, although a trend developed whereby ex-military aircraft were purchased, modified and operated by civilian companies under contract. Deutsche-Luftfahrt Beratungsdienst of West Germany and Svensk Flygtjänst AB of Sweden were two notable companies in the field in the post-war years, operating such types as the Hawker Sea Fury, Fairey Firefly and Douglas Skyraider. Many air arms however continued to operate target tugs on their own behalf. In later years the use of civilian companies expanded significantly worldwide, with many companies forming or entering the field in the 1960s and 1970s. The trend was still to use ex-military aircraft, for example Fawcett Aviation in Australia used two ex-RAAF CAC Mustangs from 1960 until the latter part of the 1970s. Flight Systems Inc. commenced operations at Mojave, California with Canadair Sabres converted as QF-86E missile targets, the first aircraft making its first unmanned flight in April 1975; this company later also operated Sabres as target tugs. Flight Systems Inc was later purchased by Tracor and these operations are still performed by BAE Systems Flight Systems with Douglas Skyhawks. The practice of using ex-military aircraft as target tugs (and of air arms retaining older aircraft themselves for such use) resulted in them surviving into an era where such aircraft became desirable as Warbirds; many former target tugs are now to be found on the airshow circuit or under restoration to fly, and in aviation museums. Current usage Today, more air arms have turned to civilian companies for provision of target towing services. Many companies operating in this field today do so using modified corporate jet aircraft instead of ex-military aircraft. Advantages of operating civil aircraft types include ease of registration (it being difficult in many countries to register ex-military jets as civil aircraft), ease of maintenance and lower operating costs when compared to ex-military aircraft. Companies active in 2007 providing target towing services include FR Aviation Services Ltd. in the UK and associated companies AVdef (in France) and Falcon Special Air Services (in Malaysia) using Falcon 20s; Pel-Air in Australia using Learjets and (in something of a reversal of recent trends) EIS Aircraft Gmbh in Germany using Pilatus PC-9 aircraft. Target towing operations are not without risk. On September 17, 1994 a Golden Eagle Aviation Lear 35A was accidentally shot