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Flight Reliability

DL 1021 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 1021 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

76%
Arrive within 15 minutes
11 min
Average arrival delay
2.9%
Cancelled
6 min early
Median arrival delay

Based on 587 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon72%(89 flights)
  • Tue76%(75 flights)
  • Wed81%(77 flights)
  • Thu82%(87 flights)
  • Fri80%(89 flights)
  • Sat75%(67 flights)
  • Sun69%(83 flights)
On-time by departure window
  • 9 AM–12 PM79%(190 flights)
  • 12–3 PM73%(15 flights)
  • 3–6 PM72%(254 flights)
  • 6–9 PM82%(108 flights)
On-time trend by month
78%
May

Jun 69% → May 78% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202569%49
July 202565%57
August 202575%60
September 202593%60
October 202563%60
November 202568%50
December 202572%46
January 202680%25
February 202694%32
March 202677%48
April 202694%35
May 202678%45
Departures on time
78%
Diverted
0.5%
Flights flown
567
Months covered
12

Keep nerding

Based on 587 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.