What was the name of the plane?

As a semi-educated identification , it appeared to be a De Havilland , probably a D.H.4 , that had some minor , post WW1 , modification . As reference , I'm using "Airplanes of the World" , by Douglas Rolfe (published by Simon and Schuster , 1954) .
While on the topic of airplanes specific to the "hunting of the mad trapper" , the fine book (my opinion) entitled "The Death of Albert Johnson" , by F.W.Anderson and Art Downs (published by Heritage House) attributes the downing of Baron von Richthofen to W.R."Wop"May's "decoying" ( ! ) of the "Red Baron" ( on May's very first mission ! ! ) into the guns of fellow Canadian Airman , Roy Brown - who took credit for the killing of the German "super ace" . Worthy of note is the fact that no less than ten separate individuals have laid claim to the downing of von Richthofen . The most recent investigation of which I'm aware (2004) tends to very strongly disagree with both the "decoy" statement , and the possibility that von Richthofen was defeated by airborne M.G. fire . Computer analysis and forensics support the likelihood that the German commander was brought down when he flew directly over an Australian A.A. position , at low altitude .
Regardless , fine book - great film !