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

🇺🇸 N77598 - BOEING 737 MAX 9 - United Airlines UAL366/UA366 (DFW-EWR-BOS) - 4.5 mi away @ 36400 ft, heading NE at 593 mph. Spotted 3x before. [08:09:30 AM CST] #AA7F4E #N77598 #B39M #UNITED #UAL366 #UA366 #ADSB #ADSBbot

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

🇺🇸 N17596 - BOEING 737 MAX 9 - United Airlines UAL366/UA366, General Edward Lawrence Logan (BOS) to San Francisco (SFO) - 4.0 mi away @ 33050 ft, heading W at 461 mph. Spotted once before! [07:02:15 PM CDT] #A12F72 #N17596 #B39M #UNITED #UAL366 #UA366 #ADSB #ADSBbot