3 objects hovering & flew away too fast to be man made

~1964-68 (I would have been ~7-11) my parents called me and my 4 siblings to the living room of our house (Dash Point, north of Tacoma) to see >1 UFO hovering above the south end of Maury\Vashon Island. As I recall there were 2-3 distinct gray objects hovering ~3-5 minutes by the time I got there to watch. The UFO’s then rapidly flew to the North and disappeared from sight very quickly (~3-5 seconds). The rate of speed they flew away eliminates any airplane including military jets. It should be noted that W. Washington is home to Boeing and several military bases including McCord Air Force base. I don’t recall anyone in my family discussing this incident again. To my knowledge nobody in my immeidate familiy is a UFO enthusist and\or conspriacy theorist. Relatively level headed conventional people. As I recall this occurred during warm months therefore, ~May-October, more than likely during the summer for all of us to be home at the same time, as I recall ! in the afternoon.