Jan 9, 1967: Malta, MT at 9pm, on family farm. Family alerted by dog, family saw a large rectangular object with glowing red light along the bottom and large amber light on top moving at high speed. The object landed in a field for approximately one hour. Object suddenly disappeared as if it took off at at a high rate of speed. The next day, family went to the field were the object had landed. There were no tracks in the snow and no sign that anything had been there. (Billings Gazette, 1-20-67)
Jan 26, 1967: Havre, MT at 8:15pm. A man saw a yellow sphere with blinking yellow body lights which circled a mountain and flew off (nicap.org)
Feb 9, 1967: Chester, MT, 6:30am, Railroad foreman saw a saucer (disk) with bright body of light hovering over the railroad depot. The depot was engulfed in light, the object departed straight up. (Spokane Spokesman-Review, 2/12/67)
Feb 23, 1967 Glasgow AFB, MT, reported sighting by NICAP (no details listed)
Mar 22, 1967: Newspaper article (UPI), "UFOs Seen In Great Falls Vicinity", The Daily Inter Lake
Tuesday night, 7:45pm - 8:30pm, several persons reported seeing unidentified flying objects over the Great Falls, Vaughn, Fort Benton, and Manchester. White lights, big with a little one on top. The object was moving east to west then north to south.
Mar 23, 1967: Great Falls, MT, 9pm: Sheriffs deputies saw a yellow object with a red glow coming from top to bottom. Object hovered then flew away. Many sightings throughout the state. (Great Falls Leader, 3/24/67)
Mar 24, 1967: Belt, MT, 9pm, Truck driver outside of Belt, MT sees a dome shaped object showing bright lights and landing in a nearby ravine. ( Investigated by Project Blue Book)
What's interesting is that most of these sightings occurred between 8pm and 9pm. The Malta UFO supposedly landed in snow covered field, but on investigation no evidence that the snow had been disturbed or melted.
Four sightings occurred in a fairly straight line in the north/central portion of the state (Glasgow, Malta, Havre and Chester).
Glasgow AFB was a major SAC base which consisted of "super" Bomb Wing consisting of B-52s and KC-135 tankers. Traffic in and out of the based would have been constant with ORI alert launches, training exercises and transient air traffic.
The UFO sightings, March 22 and 23, could have had some psychological impact leading to the Oscar Flight story as told by Robert Salas.
The March 24 Belt sighting was covered by Blue Book. Despite "around the clock" observation by local and military personnel there was no evidence that anything had actually landed. The object was observed to have landed, but nothing was observed to have left the ravine. I hope to put together a blog post on this incident in the future.