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

🇺🇸 N739NK - AIRBUS S A S A321-271NX - Spirit Airlines NKS1603/NK1603, Baltimore/Washington Thurgood Marshall (BWI) to Harry Reid (LAS) - 4.9 mi away @ 39800 ft, heading W at 534 mph. Spotted once before! [09:15:47 AM CDT] #A9EDB0 #N739NK #A21N #SPIRIT_WINGS #NKS1603 #NK1603 #ADSB #ADSBbot