United States Air Force - USAF (since 1947)

In unclear circumstances, the airplane struck the west slope of Monti della Laga located near Amatrice. All four crew members were killed.
Crew:
Cpt Jess Edward Montgomery, pilot,
Cpt Albert Joseph Henrion, copilot,
Sgt Elmer Arthur Kludt, radio operator,
Cdt Frantz Egidy.

The crew was returning to his base at Carswell following a refueling mission. The approach was completed in low visibility due to the night and foggy conditions. On final, the airplane was too low and struck the ground one mile short of runway. It bounced, struck successively power cables and the roof of a building before crashing short of runway threshold. All seven crew members were injured and the aircraft was destroyed.

En route from Athens to Naples, one of the engines suffered a runaway prop. 15 passengers and the radio operator bailed out over Botricello, intending to land at a nearby emergency field. They couldn't make the field and the pilots and the engineer put the plane down intact on the beach. The slanted beach caused them to veer into the surf and the aircraft ended up in about 10 feet of water. The crew was able to exit the astrodome hatch and swim to shore. Overnight the action of the tide destroyed the aircraft. The rumors that the aircraft was repaired, flown off the beach and put back in service are untrue.
Source: http://www.joebaugher.com/usaf_serials/1953.html

The crew was engaged in a local training flight at Walker AFB, Roswell, New Mexico. Just after liftoff, while in initial climb, the airplane rolled left and right and eventually crashed in a huge explosion on a hangar at the airbase. The airplane was totally destroyed by impact forces and a post crash fire as well as two others Boeing KC-135 Stratotanker registered 57-1449 and 57-1457. All six crew members were killed as well as two employees in the hangar.

The crew was completing a local training mission at Ramey AFB, Aguadilla, consisting of touch and go maneuvers. During a night approach, the airplane went out of control and crashed short of runway. The airplane was destroyed and all seven crew members were killed.
Crew:
Col Samuel G. Porterfield,
Lt Col Keith M. Garrison,
Cpt Nabor Mendez Pelegrina,
1st Lt George G. Fetterer,
2nd Lt Kent W. Slaughter,
Cpt Robert E. Howell,
M/Sgt William R. Hill.

While overflying the Gulf of Sirte, the single engine aircraft crashed into the sea in unknown circumstances. SAR operations were conducted over a large area but no trace of the aircraft nor the 10 occupants was ever found.

The aircraft, assigned to the 384th AREFS, departed from Westover AFB on a refueling mission. The KC-97 collided with a B-52 during refueling at an altitude of about 15,000 feet. The aircraft lost the whole left horizontal stabilizer and elevator, the rudder was missing and the upper fourth of the vertical stabilizer. They made a no-flap, electrical power off landing at night at Dow AFB. Two crew members on the B-52 parachuted to safety. The plane remaining crew members continued to Springfield-Westover AFB, MA (CEF) where a safe landing was made.
Source:
https://aviation-safety.net/database/record.php?id=19591214-0

Crashed in unknown circumstances 16 km north of Oslo while cruising in foggy conditions. All four crew members were killed.

Shortly after takeoff from Tainan Airport, en route to Clark AFB in the Philippines, the airplane crashed in unknown circumstances, killing all 15 occupants.

While on a training mission, the B-52 was supposed to be refueled by the crew of a USAF KC-135 registered 57-1513. At an altitude of 32,000 feet, both aircraft collided in unclear circumstances and dove into the ground before crashing near Leitchfield. All four crew member on board the KC-135 were killed. On board the B-52, four crew members were killed while four others were able to bail out and were found alive. Both aircraft were destroyed upon impact. Both nuclear bombs on board the B-52 were recovered intact.