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

🇺🇸 N977AK - Boeing 737MAX 9 - Alaska Airlines ASA213/AS213, Washington Dulles (IAD) to Los Angeles (LAX) - 5.4 mi away @ 35950 ft, heading WSW at 527 mph. Spotted 4x before! [09:48:42 PM CDT] #AD9DB0 #N977AK #B39M #ALASKA #ASA213 #AS213 #ADSB #ADSBbot