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Flight Reliability

DL 1139 · Delta Air Lines

Atlanta → Chicago (ATL–ORD)92% of its flights flew this route. The rest (SEA–GEG) are included in these numbers.

47
Bring Snacks
WanderNerd Reliability Score
59%
Arrive within 15 minutes
32 min
Average arrival delay
1.7%
Cancelled
8 min
Median arrival delay

Based on 293 historical flights. Data through May 2026.

What the data says

The late departure is the smart one here.

DL 1139 departing between 9 PM–12 AM arrived on time 86% of the time, versus 51% between 6–9 PM.

Mondays have been rough.

DL 1139 arrived on time 71% of the time on Saturdays and just 54% on Mondays. That gap is worth planning around.

Lagging the ATL–ORD route.

DL 1139 arrived on time 59% of the time, versus 71% across the ATL–ORD route.

Well behind the Delta Air Lines network.

DL 1139 arrived on time 59% of the time, versus 81% across the Delta Air Lines network.

The breakdown

On-time by weekday
  • Mon54%(48 flights)
  • Tue55%(33 flights)
  • Wed60%(40 flights)
  • Thu55%(47 flights)
  • Fri62%(45 flights)
  • Sat71%(24 flights)
  • Sun61%(49 flights)
On-time by departure window
  • 3–6 PM—(1 flights)
  • 6–9 PM51%(216 flights)
  • 9 PM–12 AM86%(69 flights)
On-time trend by month
35%
May

Jun 50% → May 35% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202550%24
July 202548%25
August 202569%29
September 202583%30
October 202567%18
November 202568%22
December 202561%31
January 202664%11
February 202677%22
March 202641%27
April 202648%21
May 202635%26
Departures on time
70%
Diverted
0.7%
Flights flown
286
Months covered
12

Same route, other flights

Keep nerding

Based on 293 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.