Flight profile · Delta Air Lines
DL665
Atlanta (ATL) to Ontario (ONT) · scheduled 8:55 AM – 10:13 AM
How DL665 performs
905 operations, January 2024 – July 2026.
DL665 arrived on time 86.9% of the time, against 76.3% for all ATL → ONT flights, so this departure is 10.6 percentage points better than the route as a whole. Against Delta Air Lines’ own flights on this route it is 10.0 points better.
Source: US DOT Bureau of Transportation Statistics · 905 operations, January 2024 – July 2026 · If DL665 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
What stands out
How DL665 compares to other flight numbers, not just to itself.
This flight runs unusually far ahead of the carrier's own average on this route, better than 92% of 11,589 comparable flight numbers.
86.9% on time for this specific departure, against 76.9% for the same carrier's other flights on this route.
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – July 2026 · The one thing about this specific departure that ranks most extreme against every other published flight number, out of everything FlyerIntel checks — shown only when something clears a real statistical bar, not for every flight.
Where DL665 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
Ask for the position of DL665 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.
Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| DL665 | 86.9% | 1.66% | -7 min | 3.2% | 905 |
| Delta Air Lines on ATL → ONT | 76.9% | 1.30% | -4 min | 6.9% | 2,852 |
| All ATL → ONT flights | 76.3% | 1.37% | -3 min | 7.2% | 2,919 |
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – July 2026
Why DL665 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
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for DL665 on ATL → ONT. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering January 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies DL665 comes in late, and what that does to the departure.
The aircraft flying DL665 came in 15 or more minutes late on 12% 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 ATL just before it, using the tail number in the DOT file, 816 of 890 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 |
|---|---|
| DL665 | 12% |
| 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 DL665’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 January 2024 – July 2026
From pushback to gate
When it leaves ATL late, does that still matter by the time it reaches ONT?
DL665 pushes back an average of 3.5 minutes late and reaches the gate at ONT an average of 1.9 minutes early. The 5.3 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. Its 16.5 minutes on the taxiways at ATL is about what any departure from the airport in that hour spends.
On arrival at ONT, DL665 spends 5.1 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 about what any arrival at ONT spends on the ground before reaching the gate.
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 80,028 departures from ATL scheduled in the clock hour DL665 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 DL665’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – July 2026
The hour it leaves ATL
Part of any flight’s record belongs to the clock rather than to the flight. DL665 has one departure time, so this is what that time is worth.
On-time arrival rate. 80,028 departures from ATL are scheduled in the 8 AM–9 AM hour over the period, against 1,012,247 across the whole day.
DL665 is scheduled out of ATL at 8:55 AM, in the 8 AM–9 AM bank. Departures from ATL in that hour arrive on time 88.0% of the time against 78.7% across the airport’s whole day — the slot alone is worth 9.3 points better before anything about this particular flight is considered.
The two airport figures cover every departure from ATL 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 · January 2024 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does DL665 run worse on particular days?
Wednesday is historically the most reliable day and Monday the least, a gap of 5.5 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – July 2026 · Days with fewer than 120 operations are not scored.
Other routes DL665 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→ATL Ontario to Atlanta | January 8, 2024 – July 31, 2026 | 905 | 87.5% |
| SLC→IAD Salt Lake City to Washington | May 7, 2024 – June 6, 2024 | 31 | — |
| ATL→HOU Atlanta to Houston | December 16–30, 2023 | 13 | — |
| HOU→ATL Houston to Atlanta | December 16–30, 2023 | 13 | — |
| ATL→SLC Atlanta to Salt Lake City | September 5, 2023 – December 15, 2023 | 75 | — |
| LAS→DTW Las Vegas to Detroit | October 9, 2023 – November 4, 2023 | 19 | — |
| PHX→SEA Phoenix to Seattle | July 1, 2023 – September 4, 2023 | 64 | — |
| SEA→PHX Seattle to Phoenix | July 1, 2023 – September 4, 2023 | 64 | — |
Because the same number has served different journeys, the statistics above describe only the route DL665 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.
19 min late
against a median of 7 min early
Percentiles over 905 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering January 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 |
|---|---|---|---|---|
| DL665 this flight | Delta Air Lines | 86.9% | 7 min early | 905 |
| DL779 | Delta Air Lines | 65.9% | 2 min late | 650 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. DL665 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 905 records of DL665 operating ATL → 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
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