Specifically, it is a Pfalz DIIIa. Notice the exposed machine guns. The D-III had the machine guns buried in the hull, which made servicing them a pain and clearing jams a real problem for the pilot. The D-IIIa attempted to correct this problem by putting the guns back in the open, on top of the fuselage. The Pfalz were excellently made aircraft and were so strong that they became favorites for the very dangerous job of balloon-busting. The D-IIIa, along with the relocation of the machine guns, was up-engined to a 175hp Mercedes engine, compared to the D-III's original 160hp Mercedes, which slightly improved it's original top speed of around 102 mph. By April 1918, the number of D-IIIa's at the front peaked at 433 machines at the front. Their numbers fell off after that as the Albatros D-Va and Fokker D-VII's replaced them. Even so there were still some 166 still in service as late as August 1918. It was a good aircraft that never quite gained the reputation it deserved. -- Al