DL21 LondonLHR · 17:45 SeattleSEA · 20:14
DL21 by Delta Air Lines flies from London (LHR) to Seattle (SEA) for the Sat, Oct 24 departure.
estimated arrival at SEA · local time · ~52 min from now
position updated 5m ago · checking again in 90s
Live position · flown path, last 40 min
Where the minutes go
last 5 operations · gate push → arrivalThe bar is how late it left the gate; the ring is where it actually arrived. Board clocks, not estimates.
The last 30 days
arrival outcome per operationmedian arrival −35 min · 1 cancelled · 5 operations tracked
The route today
live boardsWeather lens
Delay & cancellation outlook for this flight
Measured, 90-day sampleConditions at LHR and SEA are near their clear-air norm right now, so this reflects the route's recent baseline rather than a weather penalty. For this route and airline, under conditions like today's, over the last 90 days.
Pro Flight Search tracking, 90 days · the weather × delay correlation study → · live weather risk by airport →
When it flies
scheduled departuresEach mark is a scheduled departure at its origin-local time. Today is highlighted.
Other London to Seattle flights today
same route · Delta Air LinesIf DL21 is cancelled, this is the other Delta Air Lines nonstop flight from London to Seattle on the same day, with scheduled departure times in LHR local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →
How DL21 actually runs
Pro Flight Search has tracked every published board update for DL21 across the LHR and SEA boards: schedule changes, gate pushes and actual clocks. Usually departs ~46 min late. Based on 4 confirmed departures · 0/4 within 15 min of schedule.
The verdict above is that record speaking, so it reflects how DL21 operates rather than what the timetable promises. Numbers refresh as new flights operate.
How this operation is measured
Board log
scheduled → actual, per operationBoard clocks recorded as LHR and SEA published them.
Planning around DL21? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
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Pro Flight Search — DL21 London to Seattle on-time performance, measured from the LHR and SEA airport boards.
https://proflightsearch.com/flight/DL21
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