"Operation Bulldog – held in September 1949, and overseen by the UK’s Fighter Command and Bomber Command – was a show of strength to the Soviets. It demonstrated that the West could take swift and decisive action in the event the Russians flexed their muscles a bit too much. And, for good measure, the operation also involved the air-forces of the United States, Belgium, France, and Holland. The Soviets took careful and concerned notice, which was the whole point. It appears it was not just the Russians that kept a beady eye on the military maneuvers. Just possibly, entities from another world did likewise.
"At the time Bulldog was held, the late J.R. Oliver was a radar-operator at a British Royal Air Force base called Sandwich,
which was situated in the English county of Kent. Oliver said: “Even so
long ago, it was almost impossible to fly a glider across the [English]
Channel without it being plotted. The exercise was structured in such a
way that the technical resources and personnel of the defensive screen
were stretched to the limit.”
And here's my complete article...