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

🇺🇸 N948AK - Boeing 737MAX 9 - Alaska Airlines ASA375/AS375, Washington Dulles (IAD) to Seattle-Tacoma (SEA) - 4.1 mi away @ 34025 ft, heading W at 533 mph. Spotted once before! [10:53:25 AM CDT] #AD2AEA #N948AK #B39M #ALASKA #ASA375 #AS375 #ADSB #ADSBbot