I video record all my flights. I had fueled and was going through my pre-flight checklist. On video playback, I saw this unexplained streak of light. It seemed too slow to be a "shooting star", plus it was in the daylight. The video is facing the sun, so it shouldn't be a reflection. I assumed this might be space junk burning up on re-entry, but frame by frame shows only a white ball, with no trail or smoke. There were no Iridium flares locally at that time. I did not witness this live, only on playback from my GoPro. This was filmed at our airport. Geographic coordinates are 50 degrees 01' 11.43" N, 110 degrees 43' 34.59" W. Our airport has an elevation of 2351 feet above see level. The video is aimed at approximately 318 degrees true/ 330 degress magnetic. I see a white streak in the sky, approximately 30-35 degrees above the horizon. In the video it passes from right to left (north to south), until it's lost under the top wing. I can't tell if it is rising, or simply passing from north to south.In the video attached, it occurs around the 9 second mark. I'm not saying it's a real UFO, but I certainly can't explain this.I do have a full length digital video saved, but it is only seen in this short clip.