From BWI I see January 21 through March 11 available to Brussels, Dublin, Frankfurt, London, and Iceland. There are similar offerings from Newark, Detroit, and Boston. This sale ends January 18 but limited inventory will sell out faster than that.
These are one way fares. Return flight costs are higher. It doesn’t appear to say in the press release or on the sale promotion page (though there’s a link to terms) that the pricing requires booking a roundtrip but when I book one way only $49 flights become more expensive. Likely illegal but when you’re in this fragile a financial shape and with the US Department of Transportation shuttered, why not?
Here’s a search for January 22, Baltimore – Reykjavik – London Gatwick as the first part of a roundtrip journey — $49 fare available.
Searching one way the same flights jump to $180.
Still on a roundtrip basis you can book for under $230:
You’ll pay for bags and seat assignments. Nonetheless, while not the most comfortable flight experience (I do my best to fly in premium cabins) and made available during off season this pricing is insane.