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

🇺🇸 N17126 - Boeing 757 224/W - United Airlines UAL2127/UA2127 (SEA-LAX-EWR) - 5.0 mi away @ 37800 ft, heading ENE at 583 mph. Spotted 2x before! [03:24:59 PM CDT] #A11FA1 #N17126 #B752 #UNITED #UAL2127 #UA2127 #ADSB #ADSBbot