Okay, I mean in the technical sense. U as is "unidentified", not as in "ohmigawd aliens kidnapped my Corgi". And "flying" might be giving it a bit too much credit . . . let's say, instead . . .
. . . falling.
On the other hand it was also glowing bright blue, so I figure that's got to be worth some points.
I'm driving down 101 going sort of northwestish (since that's the direction 101 goes at that point) and a bright blue . . . something . . . seems to fall out of the clouds. Takes about half a second to reach the horizon, if I'm remembering right. About the size of a dime held at arm's length.
What was it? I have no idea. Flare? Asteroid? Satellite? Swamp gas? Tesla death ray?
There you have it, anyway.