Skip to content
WanderNerd
Check a flight

Flight Reliability

DL 4921 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 4921 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

79%
Arrive within 15 minutes
6 min
Average arrival delay
1.1%
Cancelled
7 min early
Median arrival delay

Based on 439 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon77%(64 flights)
  • Tue93%(54 flights)
  • Wed87%(54 flights)
  • Thu82%(66 flights)
  • Fri66%(65 flights)
  • Sat84%(63 flights)
  • Sun69%(67 flights)
On-time by departure window
  • 6–9 AM89%(158 flights)
  • 9 AM–12 PM81%(85 flights)
  • 3–6 PM65%(95 flights)
  • 6–9 PM74%(95 flights)
On-time trend by month
78%
May

Jun 61% → May 78% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202561%28
July 202559%27
August 202554%28
September 202589%28
October 202581%32
November 202579%29
December 202560%30
January 202693%29
February 202686%44
March 202694%62
April 202688%41
May 202678%55
Departures on time
82%
Diverted
0.2%
Flights flown
433
Months covered
12

Keep nerding

Based on 439 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.