Other / Unknown
No Specific Anomaly Occurred All Types
General None Reported / Taken
Environment - Non Weather Related; Human Factors
While enroute to ACK; almost directly over BOS at FL190; the co-pilot noticed an aircraft below us at our approx 1-2 o'clock position. At the time we were just given direct to LFV VOR. The aircraft did not show up on TCAS. It looked white/slightly grey; had an approximate wingspan of 10-15 feet; and was traveling southbound. It also had two strobe lights on the tail. It seemed to be approximately 1;500 FT below us. It was moving away and behind us at a good rate. We told ATC about what we saw; and that it looked drone like. They did not see anything on their radar at the time.
PC12 Captain reports sighting a drone like aircraft near BOS approximatly 1;500 FT below his FL190 cruise altitude. ATC had no knowledge of the aircraft.