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Flight Reliability

DL 4991 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 4991 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

77%
Arrive within 15 minutes
11 min
Average arrival delay
2.0%
Cancelled
7 min early
Median arrival delay

Based on 537 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon71%(76 flights)
  • Tue79%(76 flights)
  • Wed72%(75 flights)
  • Thu86%(73 flights)
  • Fri80%(76 flights)
  • Sat72%(72 flights)
  • Sun76%(76 flights)
On-time by departure window
  • 9 AM–12 PM82%(315 flights)
  • 12–3 PM72%(179 flights)
  • 3–6 PM53%(30 flights)
On-time trend by month
76%
May

Jun 91% → May 76% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202591%22
July 202579%56
August 202577%34
September 202568%40
October 202576%29
November 202566%29
December 202556%25
January 202676%53
February 202688%56
March 202678%60
April 202681%58
May 202676%62
Departures on time
78%
Diverted
0.4%
Flights flown
524
Months covered
12

Keep nerding

Based on 537 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.