My fiance and I stepped outside of our apartment in southwest Portland into the parking lot to have a cigarette about 9:30pm. As per usual, we began stargazing and enjoying the sights. Almost immediately, we noticed a hovering light not unlike a star lingering in the sky. Comparing it to the other stars (and planets) in the sky, we realized the object was moving.It was ever so slight at first, moving in a very small circle, but after about ten minutes, the radius seemed to widen. Using my outstretched arm for scale, the craft began moving half of an inch at a time: first up, then down. It then began moving left and right as well with no visible pattern.This continued for the better part of twenty minutes before starting to change colors. The first color change we noticed in the object happened when an airplane (the first of six) passed through the same area of the sky, ABOVE where the object was hovering. It went from a hovering white light to a reddish, spinning light. During this time, two more planes passed above the object with plenty of room in between both crafts. With the planes in comparison for distance, the hovering object seemed closer to us than the planes. A couple more planes passed BELOW the object, but there was one in particular that was very odd to us. Coming from the north, another plane was making a direct path for the UFO, and it looked like a collision COULD be possible. However, the plane traveled BEHIND the craft hovering in the air. Another ten or fifteen minutes later, the hovering object began moving in a jagged, circular pattern almost like a curly-cue. To maintain sight of it, we had to keep changing our positions where we stood in the parking lot.It became increasingly difficult to maintain focus on the object because of powerline obstructions and treelines. Right before we lost sight of the object descending behind a large tree, it seemed to shrink down to about half of the size it started as. It was then that the color changed from a pulsating white light to a bright orange pinpoint. It shifted colors back to its original appearance of spinning white lights with the intermittent reds just before we lost sight of it completely.To debunk my fiance and I's propensity for science fiction, we had a couple of our neighbors (who are also two of our best friends) to come out and view the phenomenon with us. They witnessed noticeable movement and color change as well and kept the object in view as long as we did. Their report should be on the way as well.