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

🇺🇸 N14539 - AIRBUS A321neo - UNITED AIRLINES INC UAL787/UA787 (LGA-IAH-ORD) - 3.6 mi away @ 31400 ft, heading NNE at 502 mph. Spotted 2x before. [12:14:02 AM CST] #A0B826 #N14539 #A21N #UAL787 #UA787 #ADSB #ADSBbot