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 UAL3881/UA3881, Chicago/Rockford (RFD) to George Bush Intcntl/Houston (IAH) - 4.7 mi away @ 40025 ft, heading SSW at 498 mph. Spotted 29x before. [09:13:21 PM CST] #A070D7 #N12754 #B737 #UNITED #UAL3881 #UA3881 #ADSB #ADSBbot