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Flight Reliability

DL 3978 · Delta Air Lines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and DL 3978 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

82%
Arrive within 15 minutes
5 min
Average arrival delay
0.5%
Cancelled
7 min early
Median arrival delay

Based on 392 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon84%(64 flights)
  • Tue83%(54 flights)
  • Wed83%(54 flights)
  • Thu77%(60 flights)
  • Fri77%(60 flights)
  • Sat83%(40 flights)
  • Sun84%(57 flights)
On-time by departure window
  • 6–9 AM81%(31 flights)
  • 9 AM–12 PM87%(89 flights)
  • 12–3 PM80%(179 flights)
  • 3–6 PM80%(75 flights)
  • 6–9 PM80%(15 flights)
On-time trend by month
82%
May

Jun 85% → May 82% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202585%46
July 202579%62
August 202581%62
September 2025100%20
December 202592%24
January 202670%27
February 202681%16
March 202681%26
April 202676%46
May 202682%60
Departures on time
83%
Diverted
0.3%
Flights flown
389
Months covered
10

Keep nerding

Based on 392 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.