[2][3] It was equipped with a variety of types, including the Avro 504, Royal Aircraft Factory F.E.2b,[4] together with a number of Sopwith Pups.

[2][9] 90 Squadron flew its first operational mission on 8 July 1941, when three Fortresses set off from RAF Polebrook to attack Wilhelmshaven (although only two of them actually managed to bomb the target).

The operation did not work as expected, with 90 Squadron's Fortresses being unopposed, with the German defenders concentrating on the Hampdens and Wellingtons, shooting down two and ten respectively.

[15] Four aircraft were dispatched to Egypt in November for operations in support of the Western Desert Campaign, with the two survivors becoming a detachment of 220 Squadron in December.

[19] The unit's resources were thrown into the Battle of the Ruhr and sent to many of the German targets that were most heavily defended, including Berlin.

The Squadron suffered considerable losses over an eight-month period and found it difficult to maintain reserves of men and machines.

The Stirlings suffered from deficiencies in design, due to restrictions laid down in the original Air Ministry specifications.

The last raid was to Bremen on 22 April 1945, the squadron flew 4,613 operational sorties for Bomber Command during the war and lost 86 aircraft.

Another was a biography of Wannop's tail gunner (James Cyril McCaffery), called 'Dad's War: The Story of a Courageous Canadian Youth who flew with Bomber Command.'

On 8 January 1953 a Washington from the squadron WF502 mysteriously crashed near Llanarmon-yn-Ial in Denbighshire with the loss of all 10 crewmen, it had flown into the ground at night.

[3][22] The squadron started to convert to an in-flight refueling mission in August 1961, becoming a dedicated tanker unit on 1 April 1962 when it officially lost its bomber role.