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

🇺🇸 N917AK - Boeing 737MAX 9 - Alaska Airlines ASA416/AS416, Washington Dulles (IAD) to Seattle-Tacoma (SEA) - 4.5 mi away @ 37450 ft, heading W at 484 mph. Spotted 7x before! [08:17:12 PM CDT] #ACB0B6 #N917AK #B39M #ALASKA #ASA416 #AS416 #ADSB #ADSBbot