DL4639 BUF → DTW

Delta Air Lines · Buffalo, NY to Detroit, MI · 37 flights observed, 2026-01-19 to 2026-06-05 · 241 mi

This flight is usually on time, but has a real long-delay tail — typical (median) delay is -6 min, while the worst 10% run +66 min or later.

DL4639 covers more than one route in the data window — the stats below are for BUF → DTW, the one it has flown most recently. The others are linked under “Other routes”.

On-time arrival
81%
Median delay
-6 min
90th percentile
+66 min
Cancellation rate
3%

How often is DL4639 on time?

Across 37 flights on BUF → DTW from 2026-01-19 to 2026-06-05, DL4639 arrived within 15 minutes of schedule 81% of the time. The median arrival delay was -6 min, and the worst 10% of flights arrived +66 min or later. 3% of flights were cancelled.

Delay distribution

Arrival delay for completed flights (excludes cancellations and diversions).

ArrivalFlightsShare
Early / on-time2981%
16-30 min00%
31-60 min38%
61-120 min13%
2+ hrs38%

Performance by month

MonthFlightsOn-timeAvg delay
2026-01667%+42 min
2026-025100%-4 min
2026-052085%+3 min
2026-06560%+22 min

Performance by day of week

DayFlightsOn-time
Mon875%
Tue450%
Wed450%
Thu8100%
Fri888%
SatNo data—
Sun4100%

Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…