Choosing a flight to avoid delays

No one can promise that a particular flight will be on time. What the record supports is narrower and still useful: some choices are worth far more than others. This guide puts them in order of how much they matter, and names the FlyerIntel tool that answers each one for your own airport, route and date.

1. Choose the hour first

Departure time is the first thing worth choosing: it is entirely in the traveler’s hands, and the spread in the data is wide. Flights scheduled to leave in the 5–9 AM window arrived on time 88.5% of the time, against 68.8% for the 6–9 PM window. The morning window beat the evening one at all 64 airports with enough flights in both.

A likely reason is accumulation. An aircraft that starts the day on time has had no chance to fall behind, and one that has flown five legs has had several. The guide to the DOT delay causes shows the matching shift in the data: the share of delay minutes coded to a late-arriving aircraft was 20.2% in the first window and 48.5% in the evening. The match does not prove the cause, but it is what the explanation predicts. The overnight window shows the other side. It arrived on time more often than the evening (72.8% against 68.8%), but it also had the highest cancellation rate in the table, 2.15%. The first window cancelled 1.24%. A flight that is cancelled is not late, so an on-time rate alone can flatter an hour that loses flights.

The size of the effect differs by airport. When to fly shows, for any covered airport and day of the week, how each hour of the day went and how many flights are behind every figure; try it for Atlanta. A figure with fewer than 120 flights behind it is not shown.

2. Then the day of the week

By weekday, Tuesday was best at 81.6% and Sunday worst at 75.0%, a gap of 6.6 points. That is smaller than the gap between the best and worst departure windows, so the hour matters more than the day. Cancellations follow their own pattern; the weekday table on each airport page shows both. An airport’s own best and worst days are not always the network’s, which is another reason to check the airport you will use rather than the average.

3. Check the route and the flight

Once the hour and the day are narrowed, look at the specific trip. The trip planner takes an origin, a destination, a date and a time, and returns the history for that day and hour, the flights worth considering and a suggestion for when to reach the airport; for example, Atlanta to Chicago. A route page gives the route’s own record, which can differ from both airports’ averages, and a flight-number page gives the record of that flight. A flight number is analyzed only after at least 90 operations, so a page that is missing the section is telling you the sample is thin.

4. Compare airlines and airports where you have the choice

If two airlines fly your route, compare them on it: choose “Every airline on one route” and enter the route, as in Atlanta to Chicago. The tool lines up on-time arrivals, cancellations and delays, and marks a gap as clear only when it is larger than chance. FlyerIntel’s research on two airlines on one route found that the gaps between carriers last from month to month, so a difference you see is likely to be there on your date too. Where a city has more than one airport, the metro area pages compare them for a given destination.

5. Give a connection its due

A connection ties two flights together, and the first one’s delay is the second one’s problem. The connection checker takes the arrival route and the layover length and returns how often flights on that route have landed too late for a layover of that size. The research on how long a layover needs to be found that a flight due in the evening needs a longer layover than one due in the morning at every one of the busiest airports it measured, so the same layover is a different risk in the morning than in the evening.

What the record cannot do

These are averages over many flights and a long period. They shift the odds and do not decide a single trip: a storm can disrupt any hour. Cancellations in particular are concentrated in a small number of bad days, as the report nobody flies on an average day shows, so the average rate says little about an ordinary day. For holidays, which are their own pattern, the holiday planner shows each airport’s record on the days around Thanksgiving, Christmas and July 4. If a flight is cancelled or changed, the refund checker works out whether a refund is owed. And before leaning on any single figure, look at the count of flights beside it.

What this is based on

The rates in the tables are totals for departures from the 64 covered airports, July 2023 – July 2026, judged on arrival at the destination, with cancelled and diverted flights outside the on-time rate (see the guide to how it is counted). They are history, and an average over many airports hides large differences between them.

• US Department of Transportation, 14 CFR Part 234, Airline Service Quality Performance Reports Sections 234.2 (definitions) and 234.4 (what carriers report, and the cause codes).
• Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, field list The fields of the file FlyerIntel reads, including the 15-minute arrival indicator and the five delay-cause minutes.

An error in a figure or a definition can be reported on the corrections page. How FlyerIntel decides what to publish is set out in the editorial policy.

More guides

• How on-time performance is counted. The 15-minute rule, scheduled against actual times, and what happens to cancelled and diverted flights.
• Why flights are delayed: the five DOT causes. The five causes airlines report, what a late aircraft is, and where the delay minutes went.
• How to read an airport’s reliability profile. What each section of an airport page means, and how to compare airports without fooling yourself.