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

🇺🇸 N429UA - Airbus A320 232 - United Airlines UAL1214/UA1214, San Francisco (SFO) to Bozeman Yellowstone (BZN) - 4.2 mi away @ 35175 ft, heading NE at 549 mph. Spotted 22x before! [10:18:36 PM CDT] #A51ED1 #N429UA #A320 #UNITED #UAL1214 #UA1214 #ADSB #ADSBbot