Studios in Borehamwood, Hertfordshire. The film was financed privately outside the standard Hollywood studio circuit by a group of filmmakers and investors, including producer Dean Devlin and pilot David Ellison, son of Oracle Corp. founder Larry Ellison; both spent more than $60 million of their own money to make and market "Flyboys". The Nieuport 17s featured in the film included four replicas built by Airdrome Aeroplanes, an aircraft company based outside of Kansas City, Missouri. The other aircraft used were a mix of authentic aircraft (the Nieuport 17 that Franco used throughout filming was an original combat aircraft from Kermit Weeks' collection in Florida, specially brought over for the film) and replicas including Nieuport 17s, a sole Sopwith 1 1/2 Strutter and a number of Fokker Dr.I replicas. In preparing for the starring role, Franco took flying lessons. All the other main actors, except Jean Reno, were filmed in actual aircraft in anticipation of using the aerial footage in final scenes. (Reno pointedly refused the offer, with a "No thanks, I'm afraid of flying." admission). Very little other than Franco's closeups in a cockpit ultimately made it to the screen. Historical accuracy Flyboys has been widely criticized for its lack of historical accuracy. The most serious lapse was the blending of the Lafayette Escadrille with the Lafayette Flying Corps, a sub-unit where the real-life Eugene Bullard actually served. Various details of World War I fighter aircraft technology shown in the film were inaccurate. For example, the aircraft engines in the CGI scenes are pictured as not moving. On the rotary engines used in some early aircraft, the engine case and cylinders rotated, with the crankshaft bolted to the airframe. The spinning of the cylinders improved cooling and allowed for fewer parts, making the engine simpler and lighter. The propeller was attached to the crankcase (the opposite of radial engines). One operating rotary engine appears in a scene that takes place in the repair hangar. The Nieuport and Fokker aircraft used in the movie are flying replicas built with new radial engines, due to the unavailability of original-type rotary engines. This detail can be briefly seen in the final combat when the black Fokker is taking off after Rawling's ground attack at the German airfield. In the scene where Beagle is rescued, some of the German soldiers in the trench were shown wearing the Pickelhaube. By 1916, the helmet was no