Note: Elmendorf Air Force Base, 'Remembering our Heritage' document. Ran into this myself on a hunch after reading about a Douglas C-54 Skymaster with 44 people on board that vanished near the base on January 26, 1950, right when this UFO flap occurred. Not at all sure if there's a connection, but quite a coincidence.
28 Jan 1950: Lt Col Lester F. Mathison, Commander, 625th Air Control and Warning Squadron, Elmendorf AFB, reported seeing an Unidentified Flying Object (UFO) while walking from the operations building to the squadron orderly room. He described it as three reddish-orange objects about the size and shape of a pencil eraser above a small cirrus clouds approximately 25,000 to 35,000 feet above the ground. They appeared to be moving in trail, in a slightly curved line, heading north before they disappeared. Colonel Mathison called a nearby sergeant to witness the sighting. The objectives disappeared before he arrived. The Alaskan Air Command Intelligence staff ruled out the possibility that the objectives sighted were jet aircraft.
Colonel Mathison's sighting was a series of UFOs observed during the January-June 1950 period. Sergeant William Y. Harrell, a control tower operator on Elmendorf AFB, spotted two green lights at 0122 hours, 19 April, at an altitude of 200-300 feet over one of the hangars. He and an assistant observed them move in a trail formation to a position within 1,000 feet and about 25 feet above the tower. For a brief moment, one of the lights emitted a very greenish trail. Both lights increased in brightness as they came closer to the tower and appeared to be 24-36 inches in diameter, compact and circular in shape. They appeared to glow, with deep green centers fading to yellowish green on the outer edges. The lights veered away from the control tower and passed on the opposite side of the base water tower, heading southwest towards Merrill Field. The disappeared from view one mile south of Elmendorf AFB. Other personnel on the ground also observed the lights. They appeared to be traveling at 300 miles and hour as they traversed Merrill Field. Intelligence personnel ruled out other aircraft or weather phenomena.