Was working just west of seatac airport in seattle. happened to look up & this object that had no wings, blades, parachute... was hovering within the airport flight cone. after i got a few pics & a video it shot off in a ne heading almost too fast for my eyes to track. from start to finish was about 4 minutes. when it shot off it was instantly at breakaway velocity. -note: the plane taking off went between me & the unidentifiable craft.