Searching on virginatlantic.com we found flights departing LHR on Wednesday, November 21 and returning from SEA on Sunday, November 25, 2018. This is a great fare price for those heading to the States for the Thanksgiving holiday. This fare is available from October 28 through December 31, 2018. Depart on Sunday, Monday, Wednesday, or Friday.
Not heading to Seattle? Have a look all our other flight deals found today on the London-Heathrow flight page.