Roundtrip Nonstop Flight: New York to Paris/Barcelona $300 (Nov-March)

Flight available from Nov 2018 to March 2019 generally. Appears to be basic economy seats.
Sample dates:
JFK-Paris
Nov 12 – 19 $276 Nonstop
Dec 25 – Jan 3 $285 1-Stop
JFK-Barcelona
Nov 19-27 $299 Nonstop
Jan 14-21 $287 Nonstop
JFK-Madrid
Nov 20-27 $292 Nonstop