American Airlines along with Oneworld partners British Airways, Finnair, and Iberia, continue to offer incredible fares from some major cities across the U.S. to several cities in Europe. Fares are as low as $220 roundtrip if you book today.
These discounted fares are available for travel from late October through March. Travel to Europe Sundays through Wednesdays, and return from Europe Tuesdays through Fridays.
You must stay a minimum of 7-nights to get these prices and peak holiday travel times in late December and early January are blacked out.
This sale is unadvertised and fares may jump at any moment. Try many different sites if you are finding prices jumping as inventory is going quickly and may still be available on another booking engine.
Boston to Madrid $233 roundtrip, nonstop - fall travel only!
Atlanta to Madrid $247 roundtrip - fall travel only!
Basic Economy fares only include a carry-on bag plus one personal item. The first checked piece of luggage will cost $60 each-way. On some routes, it's cheaper or the same price to upgrade to a Main Cabin Economy fare. Main Cabin Economy fares include one free checked bag.
Seats will be assigned at random upon check-in for Basic Economy. You may be able to pay a fee to choose a specific seat. Main Cabin Economy fares include advanced seat assignments.
Related: Today's Best Flight Deals to Europe
Upgrading to Main Cabin Economy will cost an additional $101 - $222 roundtrip on most routes. Certain travel dates and/or routes may be much more to upgrade. This type of fare will include one free checked bag, seat selection, and the ticket will be eligible for upgrades/changes in the itinerary (fee applies).
As an example, I found a nonstop flight departing Miami MIA on Tuesday, November 19, 2019, with a return flight from Paris CDG on Wednesday, November 27, for $255 roundtrip.