Flight profile · SkyWest Airlines
OO4031
Seattle (SEA) to Ontario (ONT) · scheduled 2:30 PM – 5:10 PM
How OO4031 performs
718 operations, April 2024 – July 2026.
OO4031 arrived on time 88.3% of the time, against 81.8% for all SEA → ONT flights, so this departure is 6.5 percentage points better than the route as a whole.
Source: US DOT Bureau of Transportation Statistics · 718 operations, April 2024 – July 2026 · If OO4031 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where OO4031 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| OO4031 | 88.3% | 0.14% | -7 min | 2.1% | 718 |
| SkyWest Airlines on SEA → ONT | 89.2% | 0.14% | -8 min | 2.4% | 2,890 |
| All SEA → ONT flights | 81.8% | 1.03% | -5 min | 4.2% | 7,756 |
Source: FlyerIntel analysis of US DOT BTS data · April 2024 – July 2026
Why OO4031 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for OO4031 on SEA → ONT. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering April 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies OO4031 comes in late, and what that does to the departure.
The aircraft flying OO4031 came in 15 or more minutes late on 10% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.
Each departure is matched to the flight the same aircraft flew into SEA just before it, using the tail number in the DOT file, 698 of 717 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late |
|---|---|
| OO4031 | 10% |
| Network, same turn | 17% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often OO4031’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering April 2024 – July 2026
From pushback to gate
When it leaves SEA late, does that still matter by the time it reaches ONT?
OO4031 pushes back an average of 1.5 minutes late and reaches the gate at ONT an average of 3.6 minutes early. The 5.1 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 23.3 minutes on the taxiways at SEA, 3.0 minutes longer than a typical SEA departure in the same hour.
On arrival at ONT, OO4031 spends 4.1 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 1.1 minutes shorter than a typical ONT arrival (5.2 min).
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached ONT. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 17,574 departures from SEA scheduled in the clock hour OO4031 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at ONT (79,947 flights), not just OO4031’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · April 2024 – July 2026
The hour it leaves SEA
Part of any flight’s record belongs to the clock rather than to the flight. OO4031 has one departure time, so this is what that time is worth.
On-time arrival rate. 17,574 departures from SEA are scheduled in the 2 PM–3 PM hour over the period, against 510,205 across the whole day.
OO4031 is scheduled out of SEA at 2:30 PM, in the 2 PM–3 PM bank. Departures from SEA in that hour arrive on time 76.8% of the time against 79.1% across the airport’s whole day, so the hour OO4031 leaves in is an ordinary one for SEA and explains nothing about its record either way.
The two airport figures cover every departure from SEA to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · April 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes OO4031 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| ONT→SEA Ontario to Seattle | July 8, 2024 – July 31, 2026 | 656 | 91.0% |
| PVD→DTW Providence/Warwick to Detroit | December 22, 2024 | 1 | — |
| BHM→DTW Birmingham to Detroit | September 9, 2024 – October 6, 2024 | 24 | — |
| DTW→BHM Detroit to Birmingham | September 9, 2024 – October 6, 2024 | 24 | — |
| DTW→STL Detroit to St. Louis | September 14, 2024 – October 5, 2024 | 4 | — |
| STL→DTW St. Louis to Detroit | September 14, 2024 – October 5, 2024 | 4 | — |
| SLC→MFR Salt Lake City to Medford | September 5, 2023 – June 6, 2024 | 158 | 85.1% |
| PHX→SLC Phoenix to Salt Lake City | March 16, 2024 – April 6, 2024 | 4 | — |
| SLC→PHX Salt Lake City to Phoenix | March 16, 2024 – April 6, 2024 | 4 | — |
| SEA→PSC Seattle to Pasco | November 5, 2023 – December 15, 2023 | 35 | — |
| PSC→SEA Pasco to Seattle | November 5, 2023 – December 15, 2023 | 33 | — |
| GRB→MSP Green Bay to Minneapolis | November 18, 2023 | 1 | — |
| MSP→GRB Minneapolis to Green Bay | November 18, 2023 | 1 | — |
| DTW→IAD Detroit to Washington | October 28, 2023 – November 4, 2023 | 5 | — |
| JFK→ORD New York to Chicago | July 1, 2023 – September 4, 2023 | 66 | — |
Because the same number has served different journeys, the statistics above describe only the route OO4031 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
17 min late
against a median of 7 min early
Percentiles over 718 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering April 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| OO4027 | SkyWest Airlines | 88.8% | 10 min early | 664 |
| OO4031 this flight | SkyWest Airlines | 88.3% | 7 min early | 718 |
| AS1086 | Alaska Airlines | 70.6% | 3 min late | 665 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. OO4031 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 718 records of OO4031 operating SEA → ONT, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed