Map of the St. Louis area showing the position and track of the aircraft described in the post.

🇺🇸 N1804U - Boeing 737MAX 8 - Southwest Airlines SWA3308/WN3308, Denver (DEN) to Baltimore/Washington Thurgood Marshall (BWI) - 4.6 mi away @ 39200 ft, heading ESE at 533 mph. Spotted 47x before! [09:16:41 AM CDT] #A143A3 #N1804U #B38M #SOUTHWEST #SWA3308 #WN3308 #ADSB #ADSBbot