A loud bang was heard across Derbyshire as military aircraft were launched to intercept a passenger plane after a reported bomb threat.
Police said the noise, which was heard just after 10am on Thursday, was as a result of two RAF jets passing over the county causing a sonic boom.
The Typhoon jets were escorting a plane to London Stansted Airport.
Police and the fire service received "a large number" of 999 calls from people who feared there had been an explosion.
Several people said their homes shook by the sonic boom.