The most important engine in WWII, (Spitfire, Lancaster and P51D.)
More than that!
Armstrong Whitworth Whitley
Avro Athena
Avro Lancaster
Avro Lancastrian
Avro Lincoln
Avro Manchester III
Avro Tudor
Avro York
Boulton Paul Balliol and Sea Balliol
Boulton Paul Defiant
Bristol Beaufighter
CAC CA-18 Mark 23 Mustang
Canadair North Star
CASA 2.111
Cierva Air Horse
de Havilland Mosquito
de Havilland Hornet
Fairey Barracuda
Fairey Battle
Fairey Fulmar
Fairey P.4/34
Fiat G.59
Handley Page Halifax
Handley Page Halton
Hawker Hart
Hawker Henley
Hawker Horsley
Hawker Hotspur
Hawker Hurricane and Sea Hurricane
Hispano Aviación HA-1112
North American Mustang Mk X
Miles M.20
Renard R.38
Short Sturgeon
Supermarine Type 322
Supermarine Seafire
Supermarine Spitfire
Vickers F.7/41
Vickers Wellington
Vickers Windsor
Westland Welkin
Also note there is no P-51 on this list. The RAF called it the Mustang; the P and F designations are USAF.
My dad flew the RAF Mustangs Mark III and IV, corresponding to the P-51 C & D, as well as the Hurricane and Spitfire. Loved loved loved the Merlin engine.