British Airways, Finnair, American Airlines, and various other airlines have round-trip flights from Seattle or Portland (SEA, PDX) to London, United Kingdom (LHR) for $596-$599, NONSTOP. Flights March to April. Departures on Monday, Tuesday, Wednesday, and Sunday. 7-day minimum stay required.
This is part of a larger European Airfare sale that we mentioned earlier. There are many other European fares on sale.
A Carry-on bag and also a personal item is allowed for free. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.