The crash involved a Cessna 407 carrying four people, and a light aircraft, which only had the pilot onboard, police said. The debris from the collision stretched across several miles. No one on the ground was reported injured.
The light aircraft, described as a microlight, crashed into a field after the collision, while the Cessna came down in a nearby wooded area, authorities said.
All of the victims were believed to be adults, Warwickshire Police Det. Supt. Adrian McGee said.
McGee said both planes had taken off from Coventry Airport and both were due to return there. McGee said investigators weren't certain if either was en route to the airport at the time of the collision.
McGee said it was too early in the investigation to say if the planes had communicated with the control tower in the minutes immediately preceding the collision.
A witness, Malcolm Collins, said he saw a twin-engine plane flying over the Combe Abbey Country Park, which sits about 5 miles east of the city of Coventry.
Collins told British Broadcasting Corp. that there appeared to be no reason for the crash, which occurred just before noon (7 a.m.
"For the life of me, I can't understand why they didn't see each other," he said, noting that the skies were clear and visibility was good.
"We noticed it was flying low, and literally, within a split second, we saw a light aircraft come in from the right," Collins said. "The twin-engined aircraft struck the light aircraft and just totally destroyed it."