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Flight Reliability

WN 4021 · Southwest Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and WN 4021 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

88%
Arrive within 15 minutes
1 min
Average arrival delay
0%
Cancelled
6 min early
Median arrival delay

Based on 256 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon90%(38 flights)
  • Tue92%(36 flights)
  • Wed89%(37 flights)
  • Thu85%(40 flights)
  • Fri90%(40 flights)
  • Sat90%(31 flights)
  • Sun82%(34 flights)
On-time by departure window
  • 3–6 AM97%(59 flights)
  • 6–9 AM89%(104 flights)
  • 9 AM–12 PM81%(53 flights)
  • 12–3 PM81%(36 flights)
  • 3–6 PM—(2 flights)
  • 6–9 PM—(2 flights)
On-time trend by month
81%
May

Jun 89% → May 81% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202589%26
July 202587%31
August 202593%15
September 202592%13
October 202591%45
January 2026100%21
February 202676%21
March 202689%26
April 202685%27
May 202681%26
Departures on time
83%
Diverted
0%
Flights flown
256
Months covered
11

Keep nerding

Based on 256 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.