Ending today, Delta Airlines offers roundtrip flights to Europe from select cities in the U.S. with prices starting at $821.20. (Click on "Delta Airlines" in the top line to book this deal; all taxes are included.) That's the lowest price we could find for select routes by $5. This price is valid on flights departing from Boston, MA, (BOS) with arrival in London, England, (LHR) on May 15 and return on May 25. A 10-day minimum stay period is required. Book this travel deal today for travel through May 29. Click here to see more routes.