🇺🇸 N1803U - Boeing 737MAX 8 - Southwest Airlines SWA1040/WN1040, Baltimore/Washington Thurgood Marshall (BWI) to Phoenix Sky Harbor (PHX) - 5.0 mi away @ 40300 ft, heading W at 505 mph. Spotted 86x before. [09:53:11 PM CDT] #A14380 #N1803U #B38M #SOUTHWEST #SWA1040 #WN1040 #ADSB #ADSBbot