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Flight Reliability

DL 4121 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 4121 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

78%
Arrive within 15 minutes
11 min
Average arrival delay
0.2%
Cancelled
3 min early
Median arrival delay

Based on 406 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon82%(61 flights)
  • Tue72%(60 flights)
  • Wed82%(61 flights)
  • Thu75%(61 flights)
  • Fri78%(60 flights)
  • Sat84%(44 flights)
  • Sun74%(58 flights)
On-time by departure window
  • 12–3 PM—(1 flights)
  • 3–6 PM78%(403 flights)
  • 6–9 PM—(1 flights)
On-time trend by month
84%
May

Jun 63% → May 84% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202563%30
July 202570%53
August 202570%56
September 202588%56
October 202582%34
November 202589%28
December 202579%19
January 202669%26
February 202685%26
April 202684%19
May 202684%51
Departures on time
79%
Diverted
0%
Flights flown
405
Months covered
12

Keep nerding

Based on 406 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.