Aer Lingus via DealBase offers round-trip fall flights to Ireland, with prices starting from $421. That's the lowest price we could find for select routes by $120. Book this travel deal by July 16 for travel from September 1 through October 31. Buy Now Tips On the DealBase landing page, click on "Aer Lingus" in the top line to see this sale; we found lower fares within. We found this price on flights departing on September 11 from Boston, MA (BOS) to Dublin, Ireland (DUB), with return on September 19. All prices, dates, and booking details were valid at the time of publication.