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Flight Reliability

DL 4138 · Delta Air Lines

FAT → Salt Lake City (FAT–SLC)

100
Nerd Approved
WanderNerd Reliability Score
96%
Arrive within 15 minutes
9 min early
Average arrival delay
0.5%
Cancelled
17 min early
Median arrival delay

Based on 365 historical flights. Data through May 2026.

What the data says

Skip Thursday if you can.

DL 4138 arrived on time 100% of the time on Wednesdays. On Thursdays: 92%.

Well ahead of the Delta Air Lines network.

DL 4138 arrived on time 96% of the time, versus 81% across the Delta Air Lines network.

Ticking up lately.

DL 4138 arrived on time 98% of the time over the last three months in the data, compared with 93% in the three months before that.

The breakdown

On-time by weekday
  • Mon96%(52 flights)
  • Tue98%(52 flights)
  • Wed100%(52 flights)
  • Thu92%(52 flights)
  • Fri96%(52 flights)
  • Sat98%(51 flights)
  • Sun94%(52 flights)
On-time trend by month
97%
May

Jun 97% → May 97% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202597%30
July 2025100%31
August 2025100%31
September 202597%30
October 202594%31
November 202597%30
December 202597%31
January 202686%29
February 202696%28
March 2026100%31
April 202697%30
May 202697%31
Departures on time
96%
Diverted
0%
Flights flown
363
Months covered
12

Same route, other flights

Keep nerding

Based on 365 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.