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Flight Reliability

DL 5221 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 5221 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

66%
Arrive within 15 minutes
25 min
Average arrival delay
2.7%
Cancelled
0 min
Median arrival delay

Based on 662 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon65%(96 flights)
  • Tue71%(93 flights)
  • Wed62%(89 flights)
  • Thu62%(92 flights)
  • Fri59%(93 flights)
  • Sat77%(90 flights)
  • Sun65%(89 flights)
On-time by departure window
  • 9 AM–12 PM58%(24 flights)
  • 12–3 PM65%(402 flights)
  • 3–6 PM66%(200 flights)
  • 6–9 PM—(4 flights)
  • 9 PM–12 AM92%(12 flights)
On-time trend by month
74%
May

Jun 55% → May 74% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202555%56
July 202564%53
August 202575%60
September 202586%58
October 202573%62
November 202551%55
December 202558%48
January 202667%55
February 202652%56
March 202658%38
April 202671%44
May 202674%57
Departures on time
73%
Diverted
0.3%
Flights flown
642
Months covered
12

Keep nerding

Based on 662 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.