Blackburn Skua and Westland Welkin

The Blackburn Skua was the first monoplane aircraft to enter service with the Fleet Air Arm and the first plane to sink a major operational warship although it was already obsolescent at the start of the Second World War.
The Westland Welkin was a British high-altitude fighter developed in response to a perceived threat from very high altitude German aircraft, most notably the Junkers Ju 86P.