terdeteksi tahun lalu: CASA CN-235-300 airplane, callsign SPUD21, serial 96-6042, at Boeing Field airport, Seattle, Wash., on July 23, 2017. (Woodys Aeroimages/CC BY-NC-ND 2.0) A military spy plane of opaque origin and purpose had been flying in circles over the Seattle area for almost two weeks. S