UA3990 HoustonIAH · 09:45 LouisvilleSDF · 13:07
UA3990 by United Airlines flies from Houston (IAH) to Louisville (SDF) for the Sun, Sep 13 departure.
estimated arrival at SDF · local time · past this estimate · waiting on the board
board checked 42m ago · checking again in 45s
Board estimate · gate and arrival times. Off blocks 09:40.
Where the minutes go
last 3 operations · gate push → arrivalThe bar is how late it left the gate; the ring is where it actually arrived. Board clocks, not estimates.
The route today
live boardsWeather lens
Delay & cancellation outlook for this flight
Measured, 90-day sampleConditions at IAH and SDF 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 Houston to Louisville flights today
same route · United AirlinesIf UA3990 is cancelled, these are the other United Airlines nonstop flights from Houston to Louisville on the same day, with scheduled departure times in IAH local time. Most flights posting a delay still operate — rebooking usually only beats a very large posted delay. Every airline on this route →
How UA3990 actually runs
Pro Flight Search has tracked every published board update for UA3990 across the IAH and SDF boards: schedule changes, gate pushes and actual clocks. Early read — pattern not clear yet. Only 3 completed legs so far: departed -5 min. Not enough to call it.
The verdict above is that record speaking, so it reflects how UA3990 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 IAH and SDF published them.
Planning around UA3990? Will a delayed flight be cancelled? · Do planes make up time in the air? · How we measure
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Pro Flight Search — UA3990 Houston to Louisville on-time performance, measured from the IAH and SDF airport boards.
https://proflightsearch.com/flight/UA3990
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