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

🇺🇸 N24537 - AIRBUS S A S A321-271NX - UNITED AIRLINES INC UAL343/UA343, Chicago O'Hare (ORD) to Portland (PDX) - 4.4 mi away @ 33125 ft, heading SW at 538 mph. Spotted once before! [10:21:45 AM CDT] #A24573 #N24537 #A21N #UAL343 #UA343 #ADSB #ADSBbot