Norwegian launches nonstop flights from Denver and Seattle to London Gatwick LGW in mid-September. One-way ticket prices start at $200 on both routes with widespread availability for flights September to March 2018, excluding late December holiday season weeks.
Norwegian Air round trip prices start from $432 Seattle and $447 Denver.
Icelandair also services Seattle and Denver and offers similar round trip prices in the mid-$400s for some dates with the advantage of free checked bags and potential for an Iceland stopover.
Norwegian Airlines Seattle SEA – London Gatwick LGW – Seattle SEA
Monday Sep 25 – Wednesday Oct 4, 2017
Norwegian Airlines Denver DEN – London LGW
Add $90 one way for LowFare+ including checked bag, self-select seat assignment and inflight meals.
An even better round trip ticket price is available with Icelandair, if you need checked luggage and want a self-selected seat.
Icelandair with Iceland 3 night stopover
$470.99 round trip
Sat Nov 4 Seattle to London LGW
Sun Nov 12 London LGW to Iceland