TRAVEL

In June, Southwest canceled fewer flights than almost any US airline — and left the gate on time less often than all of them

We read all 607,577 flights the 12 carriers filed with the DOT for June 2026. Southwest canceled 0.62%, tied for the second-lowest rate of any reporting carrier — but only 60.2% of its flights pushed back on time, the lowest of the 12, and 66.0% arrived on time, also the lowest. It rarely cancels, and it leaves the gate on time less often than any of the 12: two different reliabilities the word carries as one.

Filed by the Claridas travel pod · August 23, 2026 · Updated August 23, 2026

This article contains no affiliate links. Claridas earns nothing from any carrier, airport or booking service named here.

The Facts

A traveler who screens airlines on one word — "reliable" — is usually collapsing two different measurements: whether a flight operates at all, and whether it leaves and lands when scheduled. Read across every flight the U.S. Department of Transportation logged for June 2026, those two split, and one carrier sits at opposite ends of them. The DOT's on-time database for June 2026 — the most recent month posted (file dated 2026-08-12, retrieved 2026-08-23) — records 607,577 scheduled domestic flights by the 12 carriers that report to it. Southwest canceled 744 of its 120,933 flights, a rate of 0.62% — tied with United for the second-lowest of the 12 carriers, behind only Allegiant's 0.54%. On the same flights, 72,375 of 120,210 that departed pushed back on time (within 15 minutes of schedule): 60.21%, the lowest on-time departure rate of any reporting carrier, against a high of 82.63% for Republic and 82.05% for Delta. Southwest's on-time arrival rate, 65.98%, was also the lowest of the 12; its average departure delay ran 22.6 minutes. So the carrier tied for the second-lowest cancellation rate in June was also the most likely of the 12 to leave the gate late — near the bottom of the cancellation table and dead last on punctuality, at once. The ranking does not rest on the month's worst days. Three days — June 11, 12 and 19 — carried the delay-and-cancellation spike, and Southwest logged more than 5,600 delays across them. With those three dates removed, Southwest's on-time departure rate rises only to 61.47% — still the lowest of the 12.

The Analysis

The following is analysis, not fact. The two numbers are one operating model read from two columns. Southwest flies point-to-point on short segments and holds cancellations down by completing flights rather than scrapping them — so a bad day surfaces as a delay, not a cancellation ^sspeculative. The file cannot prove the mechanism, but it shows the outcome cleanly: among the fewest cancellations, the most lateness. Because Southwest concentrates at airports it dominates, its punctuality shows up in the record as an airport trait. Of the eight worst airports for on-time departures among the 48 with at least 3,000 departed flights, six were majority-Southwest. The extreme is Dallas Love Field: 97.5% of its 6,025 June flights were Southwest's, it departed on time just 50.78% of the time — the lowest of the 48 airports — and yet it canceled only 1.18%. Southwest's own on-time departure rate at Love Field, 49.98%, ran below even its 60.21% system figure. The 149 flights Delta flew from the same airport in the same month departed on time 81.88% of the time — a different, hub-feeding network flown at different hours, so this compares operations, not identical flying, but it sits under the same sky.

Room for Disagreement

The strongest counter is that departure punctuality is not the reliability that gets you home — arrival is, and Southwest recovers some of the gap in the air: its 65.98% on-time arrival beats its 60.21% on-time departure by nearly six points of schedule buffer. It is still last on arrivals, but the margin narrows. The 15-minute cutoff is also arbitrary, and Southwest's 22.6-minute average departure delay is not far from American's 29.8 or worse than the field on every measure. And the Love Field figure carries a caveat the file can't resolve: a slot- and perimeter-constrained close-in airport with fast gate turns could depress pushback punctuality for reasons that aren't the carrier's own doing, and the within-airport Delta comparison rests on 149 flights on different routes ^sspeculative. What survives all of it is descriptive and population-complete: across every flight the 12 carriers filed for June, Southwest canceled at the second-lowest rate and departed on time at the lowest.

The View From

From the seat that books on "this airline won't cancel on me," Southwest scores near the top of June's record; from the seat that books on "this airline will leave when it says," it scores last. The industry ratings that named Southwest the best U.S. carrier this year weight completed flights, low cancellations and few complaints — a real ledger, and a different one from the departure column. One month can tell a traveler which reliability they were actually buying; it cannot forecast a single future flight ^sspeculative.

Notable

Simple Flying · 65% On-Time: Southwest Falls From America's Most Punctual To Rock Bottom In 6 Months — July 13, 2026 trade reporting on Southwest's 2026 punctuality slide — 79.75% on-time in January to 64.94% in June (OAG), with 'over 5,600 delays' across the June 19 weekend; notes Southwest kept cancellations low because its point-to-point model prioritizes completing flights over canceling them — the mechanism this piece reads out of the DOT file.
Forbes · Southwest Is The Best U.S. Airline For The Second Year, 2026 Airline Quality Rating Says — July 19, 2026 — the Airline Quality Rating names Southwest the top U.S. carrier for a second year on low cancellations, the lowest complaint rate and near-zero denied boardings; the completion-and-complaints ledger that runs opposite the departure-punctuality column.
The Points Guy · Best Airlines Report: Tips for summer travel after flight cancellations hit 3-year high — June 3, 2026 — U.S. carriers canceled roughly 3.4% of departures through March, the worst pace since 2022, per DOT data reviewed by TPG; the industry backdrop to June's numbers.

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How this was made. Models: Travel pod — Opus writer/editor · single-month DOT BTS On-Time pull, all 12 reporting carriers, U.S. domestic scheduled flights, June 2026. EXACT FILTERS (computed this run, Python csv): population = every row in the June 2026 file (607,577 flights; 12 distinct Reporting_Airline values: AA AS B6 DL F9 G4 MQ OH OO UA WN YX). On-time departure = DepDel15==0 over rows with DepDel15 present (departed flights); on-time arrival = ArrDel15==0 over rows with ArrDel15 present (arrived flights); cancel rate = Cancelled==1 / all scheduled. Southwest (WN): 744 canceled / 120,933 (0.62%, tied 2nd-lowest with UA 0.62%; Allegiant G4 lowest at 0.54%); departed on time 72,375 / 120,210 (60.21%, LOWEST of 12); arrived on time 79,005 / 119,743 (65.98%, LOWEST of 12); average DepDelayMinutes 22.6. On-time-departure range across the 12: WN 60.21% (min) to YX/Republic 82.63% (max); DL 82.05%, UA 77.39%, AA 67.99%. Storm days = the 3 highest-disruption dates (2026-06-11, -12, -19); WN off-storm on-time departure 61.47% (still min). AIRPORT: 48 origin airports had >=3,000 departed flights; DAL (Dallas Love) had the lowest on-time-departure rate, 3,024 / 5,955 = 50.78%, cancel 71 / 6,025 = 1.18%; WN share 5,876 / 6,025 = 97.53%; WN at DAL departed on time 2,902 / 5,806 = 49.98%; DL at DAL departed on time 122 / 149 = 81.88%. Of the 8 lowest on-time-departure airports (DAL 50.78%, MDW 60.36%, HOU 60.53%, BNA 61.90%, DFW 61.95%, SFO 63.76%, LAS 63.87%, BWI 65.40%), 6 were majority-Southwest by flight count (DAL 97.5%, MDW 96.6%, HOU 92.8%, BWI 77.5%, BNA 58.5%, LAS 53.2%); the other two, DFW and SFO, are majority-American and majority-United respectively. No statistical modeling; all figures are direct counts and ratios. Causal reads (point-to-point model, Love Field constraints) are NOT computed from this file and are tagged [speculative].. Publisher of Record: Unruly Labs LP. Published August 23, 2026 · last modified August 23, 2026.

Confidence. Every factual claim here is verified against a cited primary source. A marker appears only where a claim is modeled^mmodeled, speculative^sspeculative, or preprint^ppreprint — the departures from verified worth flagging.

Sources. DOT BTS — Reporting Carrier On-Time Performance, June 2026 (607,577 scheduled domestic flights; flight-level Reporting_Airline, Origin, Cancelled, DepDel15, ArrDel15, DepDelayMinutes, FlightDate). All per-carrier and per-airport cancellation, on-time-departure and on-time-arrival rates and the off-storm split computed this run from the raw CSV. Source ZIP integrity (retrieved 2026-08-23): sha256 acd9d03e223e079e54b77065015f0ce9b6de92f1f46148048600cc9813a47a6e, md5 8d188bba30d841c110cbe1075677ec19, 31,606,062 bytes. (retrieved 2026-08-23) · DOT BTS — On-Time Performance field definitions (Reporting_Airline, Cancelled, CancellationCode, DepDel15, ArrDel15; on-time = within 15 minutes of schedule) (retrieved 2026-08-23) · U.S. DOT — Air Travel Consumer Report (the monthly on-time report; on-time metric is within 15 minutes of schedule) (retrieved 2026-08-23)