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

🇺🇸 N14219 - Boeing 737NG 824/W - United Airlines UAL642/UA642, Washington Dulles (IAD) to Phoenix Sky Harbor (PHX) - 4.3 mi away @ 35750 ft, heading W at 513 mph. Spotted 16x before! [01:29:10 PM CDT] #A0ACBB #N14219 #B738 #UNITED #UAL642 #UA642 #ADSB #ADSBbot