My husband and I were taking a ride to Chehalis, Washington from the Olympia area via I-5. It was around noon on October 6, 2014. I was in awe at how beautiful the weather was and was leaning forward, looking out the front window. At first I saw a somewhat shiny object that appeared to be in the shape of a boomerang almost like this ” ) ” and straight up and down as illustrated by the parenthesis….I thought I was seeing things, and at first thought it might be an airplane. It was well above 500 feet in elevation and it did not move. I kept watching it to see if it was going to head toward SeaTac Airport, instead it simply disappeared. I never saw it again. I had just started to point it out to my husband and he said he couldn’t look because he was driving. I told him, “I think I just saw a UFO.” I’m pretty familiar with aircraft as I am retired from Boeing and knew about several of the prototypes. This did not appear to be a plane at all.