UA3999 WashingtonIAD · 08:18 New YorkLGA · 09:39
UA3999 by United Airlines flies from Washington (IAD) to New York (LGA) for the Tue, Aug 18 departure.
estimated arrival at LGA · local time
board checked 267m ago · checking again in 45s
Board estimate · gate and arrival times. Off blocks 08:00 · typical taxi-out at IAD ≈ 9 min.
The route today
live boardsWeather lens
Delay & cancellation outlook for this flight
Measured, 90-day sampleConditions at IAD and LGA 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 Washington to New York flights today
same route · United AirlinesIf UA3999 is cancelled, these are the other United Airlines nonstop flights from Washington to New York on the same day, with scheduled departure times in IAD local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →
How UA3999 actually runs
Pro Flight Search has tracked every published board update for UA3999 across the IAD and LGA boards: schedule changes, gate pushes and actual clocks. Early read — pattern not clear yet. Only 1 completed leg so far: departed -18 min. Not enough to call it.
The verdict above is that record speaking, so it reflects how UA3999 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 IAD and LGA published them.
Planning around UA3999? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
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Pro Flight Search — UA3999 Washington to New York on-time performance, measured from the IAD and LGA airport boards.
https://proflightsearch.com/flight/UA3999
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