The Secret Files»
UFOs in History»
Controversy has surrounded the status of the Estimate ever since Ruppelt wrote these words. Not one single copy appears to have survived, and some have suggested it never existed. However, Ruppelt describes reading one copy that had escaped destruction, and he described it as “a rather thick document with a black cover...stamped across the front were the words TOP SECRET.”
Included in the Estimate was a collection of UFO reports that preceded Kenneth Arnold’s sighting of 24 June 1947. The report’s authors used these to support their interplanetary theory, arguing that pre-Arnold sightings could not be dismissed as hype or rumour triggered off by media stories. Among the cases used to prove this point were “the English ‘ghost airplanes’ that had been picked up on radar early in 1947.” 
This investigation into the British records has established that six months before Kenneth Arnold’s sighting, the RAF had logged its first official report of an ‘unidentified flying object.’ Furthermore, by July 1947 when the first sightings of ‘flying saucers’ were made in the USA, the Air Ministry remained unable to explain the intruder it had logged in January of that year. This implies that an exchange of intelligence on ‘unidentified flying objects’ between the USA and UK began in 1946-47 with the ghost rocket and ghost planes. Cold War historian Richard Aldrich writes that air power was the cutting-edge of post-war strategy “and it was appropriate that Anglo-American air intelligence was in turn the cutting edge of Western intelligence co-operation.” (28)
Air Intelligence files relating to ‘Operation Charlie’ cannot be traced at the Public Record Office or the RAF Air Historical Branch at Bentley Priory. However, documents at the US National Archive show the Air Ministry’s Assistant Chief of Air Staff (Intelligence), Air Vice Marshal Sir Thomas Elmhirst, working closely with his opposite number in the US Army Air Force (General George McDonald) during the ‘ghost rocket’ alarm in 1946. Whilst the Swedes were asking the RAF “to take all possible measures to prevent the Americans finding out about Swedish full co-operation in investigating the mysterious missiles,” Elmhirst was discreetly passing all intelligence on the subject to McDonald in Washington  . Given the level of co-operation that existed between the allies post-war, we can be confident that a dossier on what Ruppelt called ‘the English ghost planes’ (Operation Charlie) would have been shared at the highest level with the Americans when Project Sign was created. What the study contained and concluded remains a mystery.
Copyright 2002 David Clarke
Acknowledgements: We wish to thank all those who have assisted this research including Group Captain William Kent, Flight Lieutenant David Richards, Flight Lieutenant Geoff Easterling, Martin Shough, Jan Aldrich, Steven Payne and Mike Hooks of The Aeroplane.