Due to solution of two of the cases, list changed on March 22, 2001. Last updated June 11, 2020.
Others have given their top-ten UFO cases. I have selected ten that have been the toughest for me to solve. Here they are, with thoughts on possible solutions in parentheses:
A red round UFO paced their airliner for miles. It dove and sped away when the pilot turned toward it. The object was below the horizon at times. (Strangely lighted military plane?? Unlikely.)
Six red circles approached their airliner from the front. The objects flipped on edge, passed underneath the plane, then reversed. They sped away ahead of the plane, joined by two more. (Menzel's searchlight theory?? Does not explain many details.)
Diamond shaped object with orbiting balls of various colors moved slowly across the sky. Each part of the diamond was the color of the orbiting ball closest to that part. (Atmospheric expansion and distortion of star?? Why only one star?)
Multicolored glowing objects milled about in a swarm seen out to sea. Each object was a different color, but did not change color. The swarm slowly drifted across the sky, always near the horizon, and was lost in the distance. (Fireworks or light show over pleasure boat??? Does not match description.)
A Blue-white object fell to the ground. A red glow was then noticed behind the trees where it had hit, with a rotating beacon effect in it. Then one red and one white object approached the car containing the witnesses from behind. Four more objects, 2 red and 2 white, followed those. The witnesses took off in the car, scared. (Several unrelated mundane events??)
A Hovering kite-shaped object scared their dogs, Originally orange. Went out as a pinpoint of light passed it. Then reappeared as gray, and then changed to orange, then to blue-white. Seen for 25 minutes. (Some kind of balloon or kite supported illumination device for night work??)
Small (around 3 foot) disc flew in B-36 prop wash for several minutes, another disc flew past plane.
Green fireballs appeared near military bases. The mystery is why there were many green meteors over NM, but nowhere else.
Ghost rockets flew over Sweden horizontally, but some fell vertically into lakes.
Top shaped object 5 feet high landed near one metal road sign, then hopped over another metal road sign. Each sign vibrated when the object came near it.