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Flight Reliability

DL 421 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 421 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

80%
Arrive within 15 minutes
6 min
Average arrival delay
0%
Cancelled
3 min early
Median arrival delay

Based on 466 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon82%(67 flights)
  • Tue78%(67 flights)
  • Wed77%(65 flights)
  • Thu88%(65 flights)
  • Fri73%(66 flights)
  • Sat85%(67 flights)
  • Sun79%(68 flights)
On-time by departure window
  • 12–3 PM78%(361 flights)
  • 3–6 PM88%(104 flights)
On-time trend by month
74%
May

Jun 68% → May 74% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202568%37
July 202574%31
August 202590%31
September 202573%30
October 202587%31
November 202583%30
December 202564%28
January 202679%57
February 202680%56
March 202685%61
April 202695%42
May 202674%31
Departures on time
82%
Diverted
0.2%
Flights flown
465
Months covered
12

Keep nerding

Based on 466 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.