Flight profile · United Airlines
UA660
Chicago (ORD) to San Diego (SAN) · scheduled 8:46 AM – 11:48 AM
How UA660 performs
621 operations, December 2024 – August 2026.
Between its first and last recorded date on ORD → SAN, UA660 averaged about one operation a day or more (621 in 621 days, cancelled ones included).
UA660 arrived on time 86.0% of the time, against 74.2% for all ORD → SAN flights, so this departure is 11.8 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 7.0 points better.
Source: US DOT Bureau of Transportation Statistics · 621 operations, December 2024 – August 2026 · If UA660 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 UA660 compares to other flight numbers, not just to itself.
This flight runs unusually far ahead of the ORD → SAN route as a whole, better than 93% of 12,358 comparable flight numbers.
86.0% on time for this specific departure, against 74.2% for every ORD → SAN flight.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 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 UA660 is right now
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| UA660 | 86.0% | 0.00% | -11 min | 4.3% | 621 |
| United Airlines on ORD → SAN | 79.0% | 0.73% | -6 min | 7.1% | 5,355 |
| All ORD → SAN flights | 74.2% | 1.07% | -4 min | 9.5% | 10,258 |
None of UA660’s 621 operations was cancelled; the route as a whole cancels 1.07%.
4.3% of UA660’s arrivals were an hour or more late, against 9.5% across ORD → SAN, so the long delays are less common on this number than on the route.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026
Why UA660 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 UA660 on ORD → SAN. Only delays of 15 minutes or more are attributed. What the five causes mean
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
Does a late aircraft delay this flight?
How often the plane that flies UA660 comes in late, and what that does to the departure.
The aircraft flying UA660 came in 15 or more minutes late on 22% 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.
Matched by tail number to the aircraft’s previous flight into ORD: 367 of 621 departures. Unknown, cancelled or diverted inbounds and gaps over 12 hours are left out.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late |
|---|---|
| UA660 | 22% |
| Network, same turn | 33% |
A long gap on the ground gives a late aircraft room to catch up before this flight pushes back.
The network row is every flight with a scheduled turn of 3 to 6 hours. How often UA660’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.
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
From pushback to gate
When it leaves ORD late, does that still matter by the time it reaches SAN?
UA660 pushes back an average of 6.5 minutes late and reaches the gate at SAN an average of 3.6 minutes early. The 10.1 minutes between those two figures are slack the published schedule already carries, so on average a late pushback on this flight is made up before the gate. It spends 30.5 minutes on the taxiways at ORD, 5.0 minutes longer than a typical ORD departure in the same hour.
On arrival at SAN, UA660 spends 5.4 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 SAN spends on the ground before reaching the gate.
Taxi-out is gate to wheels up and sits inside the scheduled block; the hourly comparison is 86,301 ORD departures. Taxi-in is landing to gate, set against 307,043 arrivals at SAN. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026
The hour it leaves ORD
UA660 has one departure time, 8:46 AM, so this is what that hour at ORD is worth.
On-time arrival rate. 86,301 departures from ORD are scheduled in the 8 AM–9 AM hour over the period, against 985,989 across the whole day.
UA660 is scheduled out of ORD at 8:46 AM, in the 8 AM–9 AM bank. Departures from ORD in that hour arrive on time 81.2% of the time against 74.2% across the airport’s whole day — the slot alone is worth 7.0 points better before anything about this particular flight is considered.
Both airport figures cover every destination from ORD, so they describe the slot, not this journey; the route comparison is above. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · December 2024 – August 2026 · Hours below 120 departures are not scored.
Other routes UA660 has flown
Carriers reassign flight numbers. UA660 also served these 22 other city pairs in the period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| PHL→ORD Philadelphia to Chicago | January 6, 2026 – August 10, 2026 | 160 | 86.8% |
| SAV→ORD Savannah to Chicago | April 30, 2026 | 1 | — |
| BWI→ORD Baltimore to Chicago | March 5–28, 2026 | 18 | — |
| RDU→ORD Raleigh–Durham to Chicago | June 26, 2025 – July 31, 2025 | 26 | — |
| SYR→ORD Syracuse to Chicago | December 19, 2024 – March 29, 2025 | 101 | 75.2% |
| SAN→IAD San Diego to Washington | February 13, 2025 – March 29, 2025 | 45 | — |
| PIT→ORD Pittsburgh to Chicago | October 27, 2024 – December 18, 2024 | 48 | — |
| DTW→ORD Detroit to Chicago | November 22–24, 2024 | 2 | — |
| ORD→LAS Chicago to Las Vegas | February 15, 2024 – October 26, 2024 | 240 | 88.1% |
| BOS→ORD Boston to Chicago | June 27, 2024 – October 26, 2024 | 121 | 94.1% |
| ORF→ORD Norfolk to Chicago | May 23, 2024 – June 26, 2024 | 35 | — |
| MEM→ORD Memphis to Chicago | February 15, 2024 – May 22, 2024 | 98 | 90.8% |
| LAS→SFO Las Vegas to San Francisco | January 9, 2024 – February 14, 2024 | 37 | — |
| SFO→EWR San Francisco to Newark | February 1–14, 2024 | 14 | — |
| PHX→SFO Phoenix to San Francisco | December 21, 2023 – January 8, 2024 | 16 | — |
| EWR→IAD Newark to Washington | December 24, 2023 – January 7, 2024 | 3 | — |
| DFW→IAH Dallas–Fort Worth to Houston | December 1–13, 2023 | 13 | — |
| ORD→PHX Chicago to Phoenix | November 28–30, 2023 | 3 | — |
| IAD→CLE Washington to Cleveland | October 30, 2023 – November 27, 2023 | 21 | — |
| ORD→BZN Chicago to Bozeman | October 29, 2023 – November 26, 2023 | 9 | — |
| DSM→ORD Des Moines to Chicago | July 1, 2023 – October 28, 2023 | 111 | 87.9% |
| ORD→SNA Chicago to Santa Ana | July 1, 2023 – September 4, 2023 | 66 | — |
The figures above describe only ORD → SAN, the route UA660 flies now.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
29 min late
against a median of 11 min early
Percentiles over 621 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering December 2024 – August 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA660 this flight | United Airlines | 86.0% | 11 min early | 621 |
| UA2683 | United Airlines | 82.9% | 8 min early | 881 |
| AA2131 | American Airlines | 76.3% | 5 min early | 663 |
| AA1543 | American Airlines | 64.9% | 3 min late | 1,029 |
Among all 4 departures on this route with at least 600 operations, UA660 has the highest on-time rate. Every departure here has at least 600 operations; the other rows are the most punctual on the route, not all of them.
Data and methodology
Calculated by FlyerIntel from 621 records of UA660 operating ORD → SAN, 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 reported separately, not in the on-time rate.
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