Which Airline Has the Most Delays? How DOT Ranks U.S. Carriers Each Month

People search which airline has the most delays expecting one permanent loser. U.S. government data works differently. The U.S. Department of Transportation (DOT) publishes fresh carrier rankings every month, and the airline at the bottom of that month's table is the one with the most delays among reporting major carriers — until the next report arrives.

The official answer lives in DOT Table 1

DOT's Air Travel Consumer Report (ATCR) is the authoritative U.S. source for comparing airline punctuality. The flight-delay section includes Table 1, which ranks reporting marketing carriers by the percentage of arrivals that were on time across their domestic networks for that month.

Read it this way:

• Rank 1 — highest on-time arrival percentage that month (fewest delays among reporting majors).
• Last rank — lowest on-time percentage (most delays among reporting majors that month).
• Year-to-date tables — same idea, averaged across months already published in the current calendar year.

There is no lifetime trophy. A carrier that struggled in winter can rank mid-pack in summer. Always check the latest published month on DOT's Air Travel Consumer Reports page rather than a blog roundup from six months ago.

The August 2026 edition covers June 2026 flight-delay data (plus January–June year-to-date figures). When you open the PDF or tables, go straight to Table 1 for the current marketing-carrier ranking.

Which airlines are even in the ranking?

Not every U.S. airline appears. BTS TranStats notes that on-time data are reported by the 17 U.S. air carriers that have at least 0.5 percent of total domestic scheduled-service passenger revenues. Smaller charter or regional brands you booked through a codeshare may roll up under a major marketing carrier's network row in Table 1.

That 0.5 percent revenue threshold is why the table compares large scheduled carriers — the ones most travelers mean when they ask which airline delays the most — rather than every aircraft operator in the country.

How to check a specific airline or flight

Table 1 answers "who was worst among majors this month?" It does not show whether your 6 a.m. departure from Denver usually runs late. For that granularity, use BTS TranStats:

1. Open the Airline On-Time Statistics index (data run from January 1995 through June 2026).
2. Choose a report type — by Airline, Origin Airport, Destination Airport, or Flight Number.
3. Pull departure and arrival statistics, including scheduled times, actual times, departure delay, cancellation, and diversion fields.
4. Compare several months if you fly the same route repeatedly; one bad weather week can skew a single month.

Many airline apps show a one-digit on-time code on individual flights in booking systems; DOT explains those codes in the ATCR methodology section. TranStats is the public dataset behind those summaries.

Why the "most delayed airline" changes and why your flight still matters

Even the best-ranked carrier can delay you on a day the National Airspace System is saturated. The FAA provides air traffic services across more than 29 million square miles, moving more than 45,000 flights and 2.9 million airline passengers daily. On average the FAA handles 44,360 flights per day. Ground delay programs, ground stops, late inbound aircraft, crew, and maintenance can stack on top of network-wide congestion.

That scale matters when you interpret rankings. Table 1 measures how each carrier performed against its own schedule across its network — not whether the entire system was running smoothly. A hub-heavy airline and a point-to-point airline face different delay profiles even on a calm weather day.

When a specific flight slips, start with the operating airline. The FAA's command-center FAQ states that air traffic control does not cancel flights and directs passengers to the airline for cancellation reasons. The same practical rule applies to delay explanations: FAA airport status shows conditions; your carrier names the cause for your flight. See why your flight is delayed for that split.

Table 1 vs. delay causes

On-time percentage tells you how often flights arrived late; it does not by itself say why. Later ATCR tables break out delay causes — air-carrier (within airline control), extreme weather, national aviation system, security, and late-arriving aircraft — by carrier. Use those when you are deciding whether a chronic problem is airline-controlled or mostly traffic and weather.

Rankings also differ from passenger-rights questions. DOT's cancellation and delay dashboard tracks voluntary rebooking, meal, and hotel commitments for controllable disruptions — a separate question from monthly punctuality tables. If you are already stuck, read cancellations and delays: what to do next and what to do when flights are canceled.

A quick comparison: what to trust

Source	Best for	Updates
DOT Air Travel Consumer Report Table 1	Official monthly rank of major marketing carriers by on-time arrivals	Monthly (typically by the second week of the following month)
BTS TranStats On-Time database	Airline, airport, route, or flight-number history back to 1995	Through June 2026 in the public index
Operating airline app or desk	Live status and stated cause for your ticketed flight	Real time
FAA NAS Status / airport status	Airport-wide ground stops, ground delay programs, and weather capacity	Real time

Monthly rankings and live operations can disagree on any given day — a historically punctual airline can still strand you behind a ground stop. Save your boarding pass and gate offline before you need them; see delays and cancellations planning for the trip-level checklist.

DOT rankings, FAA traffic programs, and airline policies change. Confirm the current month's Table 1 on transportation.gov and your operating carrier's status before you rebook or abandon a trip.