What Airline Has the Most Delays? Latest DOT Ranking

Which airline has the most delays?

Spirit Airlines had the worst on-time rate in the latest comparable U.S. Department of Transportation ranking. In the DOT Air Travel Consumer Report covering January through June 2026, 59.84% of Spirit's reported marketing-carrier operations arrived on time. That distinction matters. A very large airline can have more delayed flights in total simply because it operates far more flights, even while a smaller airline gives an individual passenger a greater statistical chance of arriving late. For comparing a booking decision, the on-time percentage is usually the more useful answer to “what airline has the most delays?”

Latest DOT airline delay ranking

The table below uses DOT's reporting marketing-carrier results for January through June 2026. Marketing-carrier data groups a major airline with flights sold under its code, including branded regional partners where applicable. Spirit's year-to-date line reflects 47,202 scheduled operations. DOT showed Spirit as unavailable for June and did not publish a June or year-to-date rank in its month-by-month table, but its separate year-to-date marketing-carrier table still lists Spirit's 59.84% result in ninth place. That reporting caveat belongs beside the answer, not hidden below it.

What DOT means by “delayed”

DOT's Bureau of Transportation Statistics defines an on-time arrival as one that reaches the gate less than 15 minutes after its published arrival time. In other words, this ranking is not based on every flight that lands a few minutes behind schedule. It uses a consistent federal reporting threshold.

The Air Travel Consumer Report covers scheduled nonstop flights marketed and operated between points within the United States, including territories, by qualifying reporting carriers. The June report says the reporting threshold covers U.S. carriers with at least one-half of one percent of total domestic scheduled-service passenger revenue. It is a strong comparison for reported U.S. domestic service, not a universal ranking of every airline worldwide.

BTS also warns that arrival-delay figures on its public analysis pages may not match the Air Travel Consumer Report. Use one dataset, one time period, and one carrier definition when comparing airlines. Mixing a monthly operating-carrier statistic with a year-to-date marketing-carrier statistic produces a ranking that looks precise but is not comparable.

Marketing carrier versus operating carrier

The airline name on the booking may not be the airline flying the aircraft. DOT therefore publishes two views:

• Marketing carrier: the airline whose code sells the flight. Its network figure can include branded codeshare partners.
• Operating carrier: the airline that physically operates the aircraft.

For shopping, marketing-carrier results are the clearer starting point because they follow the brand a traveler chose. For diagnosing a particular regional flight, the operating carrier can be more revealing. The DOT report identifies branded partners for American, Alaska, Delta, and United and publishes separate network and operating-airline lines.

The distinction changes some positions. Always check whether a chart says “network,” “marketing,” or “operating.”

Why a delay ranking cannot predict your flight

An airline-wide average compresses many routes, airports, seasons, and causes into one number. BTS identifies several delay categories: an air-carrier delay, a late-arriving aircraft, a National Airspace System delay, a security delay, and extreme weather. The agency explains that an air-carrier delay covers circumstances within the airline's control, while a late-arriving-aircraft delay means the same aircraft reached its previous stop late.

The National Airspace System category can include airport operations, heavy traffic volume, air traffic control, and non-extreme weather. Extreme weather is reported separately. A low airline-wide rate therefore tells you what happened across a reporting period; it does not prove the cause of a specific delay or guarantee the result of the next flight.

Route-level context matters too. A nonstop avoids the extra failure point created by a connection. If two itineraries are otherwise acceptable, compare the exact flight's recent record in the reservation system and leave a realistic connection buffer. For disruption planning, see why your flight is delayed and what happens after a missed connection caused by a delay.

How to use the ranking before booking

1. Compare the same reporting period. A difficult month for one airline should not be compared with another airline's full-year result.
2. Use the marketing-carrier column first. It reflects the network sold under the airline code on your itinerary.
3. Check the operating carrier. Look for “operated by” in the itinerary, especially when a regional airline will fly the segment.
4. Inspect the exact flight. DOT says individual-flight performance is displayed in computer reservation systems used by airlines and travel agencies.
5. Plan for recovery. Prefer an itinerary with workable alternatives if arriving late would cause a missed event, separate-ticket connection, or other expensive consequence.

No historical ranking can promise an on-time trip. It can help you compare risk, but schedule, route, airport, weather, and the availability of backup flights also shape how disruptive a delay becomes.

What to do when your flight is delayed

First, keep the boarding pass and itinerary accessible and monitor the airline's app, airport displays, and messages. A delay can also “creep” longer as weather or a mechanical problem develops, so do not rely on the first estimate alone.

Second, ask the airline to identify the cause. DOT's cancellation and delay dashboard applies to controllable disruptions—essentially airline-caused events such as maintenance or crew problems. Airline commitments differ, but the dashboard shows what each carrier has promised for rebooking, meals, hotels, transportation, or other amenities. A dashboard commitment is not the same thing as a benefit owed for every weather or air-traffic delay.

Third, decide whether you still want to travel. DOT says a passenger is entitled to a refund when an airline cancels a flight, regardless of reason, and the passenger chooses not to travel or accept the alternatives offered. DOT also recognizes refunds for a significant delay or change when the traveler rejects the changed trip or other compensation. If you accept a rebooked flight or continue on the significantly changed itinerary, DOT says you are not entitled to the ticket-price refund under that rule.

For a broader recovery checklist, read what to do during cancellations and delays and when flights are refundable.

The practical answer

If “most delays” means the highest likelihood of a late arrival in the latest DOT year-to-date comparison, the answer is Spirit. If it means the greatest raw number of delayed flights, the ranking can change with airline size, and the DOT percentage table does not answer that question directly.

Use the ranking as one booking signal, then check the exact flight, operating carrier, and recovery options. Data and airline commitments change; confirm the latest result and your carrier's current policy on the official DOT and airline pages before flying.