Flights London → Washington — September 20, 2026

One way · Economy · 1 adult · price per person

The cheapest itinerary observed for Sunday, September 20, 2026 on the London–Washington route: 2 stops itinerary (3 flights) via Montreal (YUL) and Toronto (YTZ), from London Gatwick (LGW) to Washington Dulles (IAD), first flight Air Transat TS729, departs 11:35 AM, arrives 10:45 AM the next day, total travel time 28h 10m including layovers, flight time 10h 31m (layovers excluded), $543 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes not allowed, non-refundable. Price found in an Aviasales search on September 5, 2026 and read by AirSource on September 10, 2026, 19:03 UTC: it is not guaranteed and is confirmed on Aviasales at booking time. The cheapest direct flight observed: United Airlines UA7807, from London Heathrow (LHR) to Washington Dulles (IAD), departs 4:40 PM, arrives 8:15 PM, direct, 8h 35m, $1,059 per person. Fare as listed by Aviasales: carry-on bag not included (personal item only), checked bag not included, changes not allowed, non-refundable.