On Time,
Honestly

When a flight is at least fifteen minutes late, the airline codes the reason into one of five federal buckets. The single biggest is the most quietly damning: late-arriving aircraft - the same jet, running behind from its last leg, dragging the delay downstream all day. Read as a share of total delay minutes.

1. 01

   Late-arriving aircraft

   42%

   the cascade: a plane that lands late leaves late

2. 02

   Air carrier

   34%

   crew, maintenance, bags - inside the airline's control

3. 03

   National Aviation System

   18%

   congestion, ATC flow, airport ops - absorbs most weather

4. 04

   Extreme weather

   6%

   direct weather only; true weather footprint is far larger

5. 05

   Security

   0.2%

Weather looks small here - under six percent. It isn't. A thunderstorm that jams an airport gets logged as National Aviation System, and the jet it stranded becomes someone else's late-arriving aircraft tomorrow. The weather bucket counts only the storm you were sitting in, never the ones upstream.

They are closer together than the marketing suggests - the whole industry lives inside a fifteen-point band. But the order is stubborn: geography and network shape reliability. Hawaiian flies short hops in good weather; Delta runs a disciplined operation; the ultra-low-cost carriers, flying tight schedules with thin spare aircraft, sit at the bottom. Dots, not bars, because this axis starts at 65%.

Some city pairs are late almost every day, and it is rarely the airline's fault. They are short hops into the country's most crowded airspace - the New York and Chicago and Bay Area corridors - where a plane can be perfectly run and still sit on a taxiway waiting for a slot. On these routes, a third of arrivals miss the fifteen-minute line.

1. 01

   PHL → SJU

   Philadelphia to SJU

   46 min avg delay · ~4/day · see cause split
   44%

   on time
2. 02

   ORD → HSV

   Chicago O'Hare to HSV

   37 min avg delay · ~3/day · see cause split
   46%

   on time
3. 03

   DFW → ECP

   Dallas-Fort Worth to ECP

   29 min avg delay · ~5/day · see cause split
   47%

   on time
4. 04

   PHL → SEA

   Philadelphia to Seattle

   29 min avg delay · ~4/day · see cause split
   48%

   on time
5. 05

   MDW → MSP

   MDW to Minneapolis

   38 min avg delay · ~8/day · see cause split
   48%

   on time
6. 06

   FSD → MSP

   FSD to Minneapolis

   31 min avg delay · ~4/day · see cause split
   48%

   on time
7. 07

   SJU → BDL

   SJU to BDL

   51 min avg delay · ~3/day · see cause split
   49%

   on time
8. 08

   MIA → TPA

   Miami to TPA

   56 min avg delay · ~6/day · see cause split
   50%

   on time

Directional pairs; a route can behave differently in each direction. On-time = arrival within 15 minutes.

Here is the quiet trick behind rising punctuality: airlines fly no faster than they did fifteen years ago, but they now schedule more time for the same trip. Stretch the timetable and yesterday's late flight lands early today - no new engines required. The gap below is the block time added to the same city pairs since roughly 2010.

A connection is only as good as the hub it runs through. Book the same itinerary through Atlanta or through Newark and you are making a genuinely different bet on whether your bag - and you - make the second flight. On-time departure rate for each major hub; the line marks the national average.

national average, 75%. On-time = departure within 15 minutes of schedule.

A delay is an inconvenience; a cancellation is a broken promise. The worst days in modern American aviation were rarely about a single storm - they were about brittle systems failing under load. These four are a matter of public record, from DOT penalties and federal investigations.

1. 01

   The Southwest holiday meltdown

   December 21-29, 2022

   Southwest Airlines ~16,700 flights

   Cause Winter Storm Elliott, then an outdated crew-scheduling system that could not re-assign crews once the network broke.

   Outcome Roughly two million passengers stranded over the holidays. In December 2023 the DOT fined Southwest $140 million - the largest consumer-protection penalty in the department's history.

2. 02

   The day the NOTAM system failed

   January 11, 2023

   Entire U.S. system ~1,300 flights, 11,000+ delays

   Cause A corrupted database file took down the FAA's NOTAM pilot-alert system overnight.

   Outcome The FAA ordered the first nationwide ground stop of departures since September 11, 2001. Traffic recovered within a day.

3. 03

   Delta and the CrowdStrike outage

   July 19-24, 2024

   Delta Air Lines (worst hit) ~7,000 flights

   Cause A faulty CrowdStrike security update crashed Windows machines worldwide; Delta's crew-tracking system took days to recover.

   Outcome About 1.3 million Delta passengers affected over five days. The DOT opened an investigation; Delta put the cost near half a billion dollars.

4. 04

   The day flying stopped

   September 11-13, 2001

   All U.S. civil aviation every flight, ~2.5 days

   Cause After the attacks, the FAA grounded all civilian aircraft and closed U.S. airspace.

   Outcome The only complete shutdown of American commercial aviation in its history. It remains the benchmark every later 'ground stop' is measured against.