Delta Airlines offers roundtrip flights to Europe from select cities in the U.S. with prices starting at $980.40. (Click on "Delta Airlines" in the top line to book this deal; all taxes are included.) That's the lowest rate we could find for select routes by $142. This price is valid on flights departing from Atlanta, GA, (ATL) with arrival in Madrid, Spain, (MAD) on April 12 and return on April 22. Book this travel deal by February 2 for travel from April 15 through May 15. Click here to see more routes.