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Flight Reliability

DL 1721 · Delta Air Lines

MOB → Atlanta (MOB–ATL)92% of its flights flew this route. The rest (SJU–BOS, SFO–LAX) are included in these numbers.

84
Pretty Reliable
WanderNerd Reliability Score
91%
Arrive within 15 minutes
7 min early
Average arrival delay
3.7%
Cancelled
15 min early
Median arrival delay

Based on 300 historical flights. Data through May 2026.

What the data says

Morning flights do better here.

DL 1721 departing between 3–6 AM arrived on time 97% of the time, versus 60% between 12–3 PM.

Monday is the weak spot.

DL 1721 arrived on time 93% of the time on Tuesdays. On Mondays: 86%.

Better than the MOB–ATL route average.

DL 1721 arrived on time 91% of the time, versus 82% across the MOB–ATL route.

Better than the Delta Air Lines network average.

DL 1721 arrived on time 91% of the time, versus 81% across the Delta Air Lines network.

The breakdown

On-time by weekday
  • Mon86%(42 flights)
  • Tue93%(43 flights)
  • Wed93%(43 flights)
  • Thu88%(41 flights)
  • Fri93%(40 flights)
  • Sat92%(39 flights)
  • Sun90%(41 flights)
On-time by departure window
  • 3–6 AM97%(34 flights)
  • 6–9 AM92%(232 flights)
  • 12–3 PM60%(15 flights)
  • 6–9 PM—(7 flights)
  • 9 PM–12 AM—(1 flights)
On-time trend by month
90%
Apr

Jun 82% → Apr 90% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202582%28
July 202597%31
August 202587%31
September 2025100%30
October 202597%31
December 202569%13
January 202693%28
February 202685%26
March 202690%31
April 202690%29
Departures on time
92%
Diverted
0%
Flights flown
289
Months covered
12

Same route, other flights

Keep nerding

Based on 300 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.