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Flight Reliability

DL 3977 · Delta Air Lines

LEX → Detroit (LEX–DTW)95% of its flights flew this route. The rest (ELM–DTW, DTW–HSV) are included in these numbers.

88
Pretty Reliable
WanderNerd Reliability Score
85%
Arrive within 15 minutes
4 min
Average arrival delay
1.4%
Cancelled
11 min early
Median arrival delay

Based on 354 historical flights. Data through May 2026.

What the data says

Sunday scaries are real for this one.

DL 3977 arrived on time 88% of the time on Tuesdays. On Sundays: 81%.

A bit ahead of the LEX–DTW route.

DL 3977 arrived on time 85% of the time, versus 82% across the LEX–DTW route.

A bit ahead of the Delta Air Lines network.

DL 3977 arrived on time 85% of the time, versus 81% across the Delta Air Lines network.

Trending in the right direction.

DL 3977 arrived on time 87% of the time over the last three months in the data, compared with 78% in the three months before that.

The breakdown

On-time by weekday
  • Mon86%(49 flights)
  • Tue88%(50 flights)
  • Wed88%(50 flights)
  • Thu88%(50 flights)
  • Fri82%(51 flights)
  • Sat85%(47 flights)
  • Sun81%(52 flights)
On-time by departure window
  • 6–9 AM85%(347 flights)
  • 12–3 PM—(2 flights)
On-time trend by month
90%
May

Jun 97% → May 90% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202597%29
July 202563%30
August 202584%31
September 2025100%24
October 202597%31
November 202593%29
December 202575%28
January 202672%29
February 202685%27
March 202670%30
April 2026100%30
May 202690%31
Departures on time
87%
Diverted
0%
Flights flown
349
Months covered
12

Same route, other flights

Keep nerding

Based on 354 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.