From Wikipedia

Four Years Of Thunder

Episode Four

In the aftermath of the Fokker Scourge the need for a larger, better equipped RFC became obvious, and the process of raising many new squadrons was started. In the short term creating new units was easier than producing aircraft to equip them, and training pilots to man them. When the Battle of the Somme started in July 1916 most ordinary RFC squadrons were still equipped with the BE.2c - the same aircraft that had proved such an easy target for the Fokker Eindecker - new types such as the Sopwith 1½ Strutter had to be transferred from production intended for the RNAS. Even more seriously, replacement pilots were being sent to France with pitifully few flying hours.

Nonetheless, air superiority and an "offensive" attitude facilitated the greatly increased involvement of the RFC in the battle itself, in what was known at the time as "trench staffing" - in modern terms close support. For the rest of the war this became a regular routine, with both the attacking and defending infantry in a land battle being constantly liable to attack by machine guns and light bombs from the air. At this time, counter fire from the ground was far less effective than it became later, when the necessary techniques of deflection shooting had been mastered.

Allied air superiority was maintained during the battle, and the increased effectiveness of Allied air activity proved disturbing to the German High Command . A complete reorganisation of the German Luftstreitkräfte followed. This reorganisation eventually produced the German strategic bombing squadrons that were to produce such consternation in England in 1917 and 1918, and the specialist close support squadrons (Schlachtstaffeln) that gave the British infantry such trouble at Cambrai and during the German Spring offensive of 1918 - but its most dramatic effect involved the raising of specialist fighter squadrons or Jagdstaffeln. By the end of 1916 these units, equipped with the new Albatros fighters, had reestablished German air superiority, in spite of their having been formed a full year after similar units had become part of the RFC and the French Aéronautique Militaire.

The first half of 1917 marked a period of German air superiority. These were successful months for the jagdstaffeln and the much larger RFC suffered significantly higher casualties than their opponents. While new Allied fighters such as the Sopwith Pup, Sopwith Triplane, and SPAD S.VII were coming into service, at this stage their numbers were small. On the other hand, the jagdstaffeln were equipped with the new Albatros D.III, which was, in spite of some structural difficulties, "the best fighting scout on the Western Front" at the time. Meanwhile, most RFC two-seater squadrons still flew the BE.2e, a very minor improvement on the BE.2c.

This culminated in the rout of April 1917, known as "Bloody April". The RFC suffered particularly severe losses, although Trenchard's policy of "offensive patrol", placing most of their flying on the German side of the lines, was maintained.

During the last half of 1917, the British Sopwith Camel and S.E.5a and the French SPAD S.XIII became available in numbers. The ordinary two seater squadrons in the RFC received the R.E.8 or the F.K.8, not outstanding warplanes, but far less vulnerable than the BE.2e they replaced. The F.E.2d at last received a worthy replacement in the Bristol F.2b. On the other hand the latest Albatros, the D.V proved to be a disappointment, as was the Pfalz D.III. The exotic Fokker Dr.I was plagued, like the Albatros, with structural problems. By the end of the year the air superiority pendulum had swung once more in the Allies' favour.

The final year of the war (1918) saw increasing shortages of supplies on the side of the Central Powers. Captured Allied aircraft were scrounged for every available material, even to the point of draining the lubricants from damaged engines just to keep one more German aircraft flyable.

Manfred von Richthofen, the famed Red Baron credited with around 80 victories, was killed in April, possibly by an Australian anti-aircraft machinegunner (although Royal Air Force pilot Captain Arthur Roy Brown was officially credited), and the leadership of Jagdgeschwader 1 eventually passed to Hermann Göring.

Germany introduced the Fokker D.VII, both loved and loathed to the point that the surrender of all surviving examples was specifically ordered by the victorious Allies.

This year also saw the United States increasingly involved. While American volunteers had been flying in Allied squadrons since the early years of the war, not until 1918 did all-American squadrons begin patrolling the skies above the trenches. At first, the Americans were largely supplied with second-rate weapons and obsolete aircraft, such as the Nieuport 28. As American numbers grew, equipment improved, including the SPAD S.XIII, one of the best French aircraft in the war.