Anthony Fokker personally demonstrated the system on 23 May 1915, having towed the prototype aircraft behind his touring car to a military airfield near Berlin.

[4] Parschau had served[5] with the same surreptitiously named Brieftauben-Abteilung Ostende (BAO), in Belgium as Oberleutnant von Buttlar in November 1914, where the two German officers could have first made contact.

Parschau made several attempts at aerial combat during June 1915, but at this stage the gear proved very unreliable, the Parabellum gun repeatedly jamming.

The mid-fuselage wing mount modification was not fitted to the initial batch of five M.5K/MG production prototypes as originally built,[6] with Otto Parschau's second Eindecker, the first M.5K/MG built bearing IdFlieg serial E.1/15 (bearing Fokker factory airframe number 191, accepted by IdFlieg on 26 May 1915 with shipping date of 15 June 1915)[7] uniquely getting it sometime later, while in service.

One distinctive feature of the appearance of all the sheet metal panelling on the Eindeckers was a special form of "dragged" engine turning performed on all their surfaces, both exposed and internal parts.

For an inexperienced pilot, the extreme sensitivity of the elevators made level flight difficult; German ace Leutnant Kurt Wintgens, who along with Leutnant Parschau was the primary Fliegertruppe pilot responsible for bringing the first armed Fokker monoplanes into active service during the spring and summer of 1915, once stated "lightning is a straight line compared with the barogram of the first solo".

Total production for the entire Fokker E.I through E.IV series was 416 aircraft (the exact breakdown by type is not clear, although the E.III was the most important model).

The first Eindecker victory, though unconfirmed, was achieved by Leutnant Wintgens in the late afternoon of 1 July 1915[9] when, while flying one of the five M.5K/MG production prototype/"service test" aircraft, numbered 'E.5/15' near Lunéville, he forced down a French Morane-Saulnier L two seat "parasol" monoplane.

Boelcke, Immelmann, Parschau, Hans Berr, and Wintgens all received Germany's highest military decoration, the Pour le Mérite or "Blue Max", while flying the Eindecker, after each pilot passed the then-required eight victory total for each aviator.

The arrival in early 1916 of the French Nieuport 11 and the British Airco DH.2 brought the dominance of the Eindecker to an end, and with it, the "Fokker Scourge".

On 8 April 1916, a novice German pilot took off from Valenciennes with a new E.III (IdFlieg serial number 210/16) bound for Wasquehal but became lost in haze and landed at a British aerodrome east of St. Omer.