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Flight Reliability

DL 4978 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 4978 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

74%
Arrive within 15 minutes
13 min
Average arrival delay
2.7%
Cancelled
10 min early
Median arrival delay

Based on 370 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon78%(51 flights)
  • Tue76%(53 flights)
  • Wed73%(55 flights)
  • Thu67%(52 flights)
  • Fri74%(50 flights)
  • Sat75%(44 flights)
  • Sun74%(54 flights)
On-time by departure window
  • 6–9 AM75%(12 flights)
  • 9 AM–12 PM78%(91 flights)
  • 12–3 PM72%(256 flights)
On-time trend by month
71%
Apr

Jun 68% → Apr 71% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202568%40
July 202551%47
August 202586%62
September 202591%56
October 202574%50
December 202575%12
March 202661%41
April 202671%38
Departures on time
72%
Diverted
0.3%
Flights flown
359
Months covered
11

Keep nerding

Based on 370 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.