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

🇺🇸 N24526 - Airbus A321 271NXSL - United Airlines UAL1387/UA1387, Chicago O'Hare (ORD) to San Francisco (SFO) - 4.1 mi away @ 34025 ft, heading WSW at 531 mph. Spotted 3x before! [10:10:20 AM CDT] #A2454F #N24526 #A21N #UNITED #UAL1387 #UA1387 #ADSB #ADSBbot