Delta SkyMiles members who purchase a roundtrip flight between New York (JFK) and London (LHR) in any paid fare class by Sept. 1, 2011 for travel through Sept. 15, 2011 will receive a $100 American Express gift card.

Registration is required at http://insideflyerus.wpengine.com/link/?4901
The offer is valid on new reservations on Delta marketed and operated, or KLM marketed and Delta operated, nonstop flights from New York (JFK) to London (LHR). Members can earn a maximum of one gift card during this promotion.