We Built a Tool That Tells You the Best Time to Fly — Using 1.8 Million Real Flights
Pick your departure airport, choose a destination, and instantly see which airlines perform best and when to depart. Backed by U.S. government flight data from last summer.
We spent a lot of time with U.S. Department of Transportation flight data. We downloaded 1.8 million domestic flights from June, July, and August 2025 — the peak of summer travel season — and built an interactive tool that lets you look up any US route and see exactly which airlines perform best and when you should depart.
→ Try the US Flight Reliability Finder
Here's what we learned in the process.
The Single Most Important Finding
Fly in the morning. Across virtually every airport and route in our dataset, flights departing before 9am arrive on time at dramatically higher rates than afternoon or evening flights.
This isn't a coincidence or a seasonal quirk. It's structural. A plane that flies four or five routes per day accumulates delays as the day goes on — a late arrival in Chicago means a late departure to Denver, which means a late arrival to San Francisco, and so on. By 3pm, the entire network is carrying the weight of every delay that happened since 6am.
The data is unambiguous. On a route like LAX to JFK, departing 6–9am gives you an 11.9% chance of arriving late. Depart between noon and 3pm and that jumps to 40.6%. Same route. Same airlines. Three times worse, simply because of when you leave.
What the Tool Does
The US Flight Reliability Finder lets you:
- Select any US departure airport — 164 airports are covered, from major hubs to regional airports
- Optionally pick a destination — or leave it blank to see overall airport performance
- See airlines ranked by on-time performance, with color-coded scores (Excellent → Avoid), cancellation rates, and average delay when late
- See the best departure windows — six time slots from "Before 6am" through "6pm+", each with a score and flight count
The data covers June, July and August 2025 — 1,845,381 flights. That's a meaningful sample. A route showing 15% late rate across three months of peak summer is telling you something reliable, not a one-week fluke.
Some Highlights From the Data
Hawaiian Airlines is the best domestic carrier for reliability — but only on its own routes between Hawaiian islands, which are short, weather-protected, and operate in a self-contained network. On inter-island routes, late rates can drop below 10%. The moment Hawaiian operates longer routes to the mainland, performance degrades significantly.
SkyWest consistently outperforms the big carriers at major airports. At LAX, SkyWest's 14.4% late rate beats American (26.3%), Delta (19.5%), and United (19.4%). SkyWest operates as United Express and Delta Connection — so if you're booking a United or Delta regional flight, you may actually be getting SkyWest metal, which isn't necessarily bad news.
American Airlines has a systemic problem. Across the national dataset, American consistently ranks near the bottom for on-time performance and near the top for average delay length when things go wrong. At LAX, American's average delay when late is 93 minutes — the worst of any carrier at that airport.
Frontier's 3.8% cancellation rate at LAX should give you pause. For context, Southwest's cancellation rate at the same airport is 0.5%. If you're booking a Frontier flight and have a connection or a time-sensitive commitment at the other end, that's worth knowing.
Atlanta (ATL) is the delay capital of American aviation. Seven of the ten worst-performing routes in our entire dataset depart from or arrive at ATL or DFW. The hub structure of these airports means delays cascade rapidly across the entire network. If you're connecting through Atlanta on a summer afternoon, build in significant buffer time.
How to Use the Tool
Scenario 1: You have a flexible schedule Select your departure airport without a destination. The tool shows you overall airline rankings for that airport — useful if you're deciding which carrier to book before you've committed to a route.
Scenario 2: You've already picked a route Enter both airports. The tool narrows to just the airlines that fly that specific route, ranked by performance. The time-of-day grid shows you exactly which departure windows to target and which to avoid.
Scenario 3: You're comparing airports Run the tool for LAX, then BUR, then SNA. You'll quickly see that Long Beach (LGB) consistently outperforms the others in the LA basin — useful if your destination is served from multiple nearby airports.
A Note on the Data
This tool uses U.S. Department of Transportation Bureau of Transportation Statistics data — the same data the FAA, airlines, and academic researchers use. It's public domain and commercially usable. We don't scrape FlightAware or Flightradar24.
"Late" in our analysis means arrival 15 or more minutes behind the scheduled time — the standard industry definition used by the DOT. Cancellation rates include all scheduled flights whether or not they operated.
The data reflects last summer's performance. Airlines change their operations, add routes, and adjust fleets — so treat this as a strong directional signal rather than a guarantee. The time-of-day patterns are structural and highly likely to repeat. Individual airline rankings can shift month to month.
Try It
→ US Flight Reliability Finder
164 airports. 1.8 million flights. Pick your route and find out when to fly.
Data: U.S. DOT Bureau of Transportation Statistics, June–August 2025. Public domain.