We were driving north on the 405 near Long Beach when we saw 2 fighter jets fly past our car (also heading north). At first we thought this was unusual, but then we remembered it was President's Day, so we just assumed they were on their way to an airshow or something for the holiday.Shortly after (maybe 5-10 minutes later) we suddenly noticed a giant white spade-shaped object hovering over the highway (approximately 1-2 miles ahead of us). The sky was relatively clear blue with minimal whisps of cloud, so this bright white object grabbed our attention quickly. Nearby airplanes could be seen moving in the distance. This object did not move for about 30-60 seconds, so we got a rather close look at the object, which did not have any wings or appear to have any windows. It was solid white with a light grey undercarriage and very bright.Before I could take a picture, the object sped off to the north east (towards the Hills) where it ascended slowly for a moment before disappearing in the blink of an eye. One moment it was there; the next, it was not.We were both stunned and left in complete awe of this flying object. Both of us confirming with the other that, yes, we actually REALLY just witnessed an unidentifed flying object that did not look like, nor move like any aircraft we have ever seen.At that point, we started wondering whether the 2 jet fighter planes we had seen moments before we spotted the large white flying object were actually on their way to intercept it.