The first aircraft to exceed the speed of 1,000 mph in level flight was the UK's Fairey Delta 2, which set a speed record of 1,132 mph (1,822 km/hr) in 1956. The Delta 2 was a purely experimental aircraft, with just two built.
The Delta 2 was the last aircraft built by Fairey, closing out decades of aviation design and production.
The second Delta 2 was rebuilt to test the wing planform for the Concorde supersonic airliner and was known as the BAC 221 (photo).
https://en.wikipedia.org/wiki/Fairey_Delta_2