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

🇺🇸 N44522 - Airbus A321 271NXSL - United Airlines UAL747/UA747 (SEA-ORD-IAH) - 4.4 mi away @ 36100 ft, heading SW at 432 mph. Spotted once before! [09:21:19 PM CST] #A55FE9 #N44522 #A21N #UNITED #UAL747 #UA747 #ADSB #ADSBbot