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

🇺🇸 N12754 - Boeing 737NG 7V3/W - United Airlines UAL2729/UA2729, Washington Dulles (IAD) to Seattle-Tacoma (SEA) - 5.1 mi away @ 37925 ft, heading W at 518 mph. Spotted 25x before! [09:56:34 AM CDT] #A070D7 #N12754 #B737 #UNITED #UAL2729 #UA2729 #ADSB #ADSBbot