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

🇳🇱 PH-AOF - Airbus A330 203 - KLM Royal Dutch Airlines KLM661/KL661, Amsterdam Schiphol (AMS) to George Bush Intcntl/Houston (IAH) - 4.8 mi away @ 39475 ft, heading SSW at 529 mph. Spotted for first time! [12:21:25 PM CST] #484445 #PH_AOF #A332 #KLM #KLM661 #KL661 #ADSB #ADSBbot