🇺🇸 N17550 - Boeing 737MAX 9 - United Airlines UAL521/UA521, George Bush Intcntl/Houston (IAH) to General Edward Lawrence Logan (BOS) - 4.7 mi away @ 35300 ft, heading NE at 546 mph. Spotted 8x before. [08:19:38 PM CDT] #A12EE0 #N17550 #B39M #UNITED #UAL521 #UA521 #ADSB #ADSBbot