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Flight Reliability

DL 1631 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 1631 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

87%
Arrive within 15 minutes
4 min early
Average arrival delay
2.1%
Cancelled
12 min early
Median arrival delay

Based on 433 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon89%(64 flights)
  • Tue86%(63 flights)
  • Wed91%(65 flights)
  • Thu92%(59 flights)
  • Fri81%(57 flights)
  • Sat87%(54 flights)
  • Sun84%(62 flights)
On-time by departure window
  • 6–9 AM—(1 flights)
  • 9 AM–12 PM84%(133 flights)
  • 3–6 PM89%(290 flights)
On-time trend by month
86%
May

Aug 90% → May 86% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
August 202590%59
September 202582%50
October 202583%60
November 202598%48
December 202589%56
January 202677%34
February 202695%19
March 202685%26
April 202687%30
May 202686%28
Departures on time
85%
Diverted
0%
Flights flown
424
Months covered
12

Keep nerding

Based on 433 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.