Flight number record
OO 5861
SkyWest Airlines · Denver to Colorado Springs
- Route
- DEN → COS
- Departs
- 17:55
- Flights
- 347
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 5861, check with SkyWest Airlines. SkyWest Airlines flies under contract for larger airlines, so a ticket for this flight may show a different airline code and number.
OO 5861 draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 347 flights, with a median arrival 3 minutes early.
The national on-time rate over the same period is 77.3%, so OO 5861 runs 11 points behind the country as a whole. Across a thousand flights that is about 108 extra late arrivals.
Key figures
On time
66.5%
Arrivals under 15 minutes late, of 346 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
0.29%
National rate is 1.89%
1 hour+ late
15.9%
National rate is 8.3%
These figures cover 347 flights between September 2025 and August 2026. Beyond the headline rate, 15.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When OO 5861 flies
OO 5861 flies DEN to COS without a single fixed slot. Its most common scheduled departure was 17:55, used on 117 of 347 flights, with 17:25 (103 flights) and 17:54 (74 flights) next.
- Departs 17:55117 flights33.7%
- Departs 17:25103 flights29.7%
- Departs 17:5474 flights21.3%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:55 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and OO 5861 runs level with that at 66.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
OO 5861 next to DEN to COS
Every carrier on DEN to COS combined arrived on time 76.5% of the time across 4,989 flights, so OO 5861 is 10 points behind it. SkyWest flew 3,338 flights on the same city pair under all its flight numbers, including this one, and those ran 76.6% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 12 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 5861thin sample | 347 | 66.5% | 88 min | 0.29% | C+ |
| All SkyWest Airlines on DEN–COS | 3,338 | 76.6% | 73 min | 1.65% | B |
| All carriers on DEN–COS | 4,989 | 76.5% | 68 min | 1.26% | B |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 5861 quarter by quarter
OO 5861 did not run the same all year. Its best quarter was Oct–Dec 2025 at 86.7% on time and its weakest Jul–Sep 2026 at 36.7%, a swing of 50 points on roughly 69 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights73.3%
- Oct–Dec 202575 flights86.7%
- Jan–Mar 202690 flights67.8%
- Apr–Jun 202691 flights65.9%
- Jul–Sep 202661 flights36.7%
Scale runs 30% to 90%.
By weekday, OO 5861 ranged from 62.0% on Friday to 70.6% on Monday. With about 50 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late OO 5861 runs when it is late
OO 5861 often beats the schedule: 89 of 346 completed flights, 26%, arrived 15 minutes or more early. The 116 late arrivals split 25 under half an hour, 36 between 30 and 60 minutes, and 55 an hour or more.
- 15+ min early89 flights25.7%
- Within 15 min141 flights40.8%
- 15–29 min late25 flights7.2%
- 30–59 min late36 flights10.4%
- 1–2 hours late23 flights6.6%
- 2+ hours late32 flights9.2%
Scale runs 0% to 100%.
Share of 346 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 105 departures that left 15 minutes late or more, only 11 made it up before arrival. In the other direction, 22 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at COS.
The worst days
Worst days for OO 5861
The latest arrival of the period was on 21 August 2026, 6 hours 25 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 21 August 2026 | 6 hours 25 minutes | Carrier |
| 14 August 2026 | 5 hours 14 minutes | National Airspace System |
| 22 August 2026 | 4 hours 45 minutes | Carrier |
| 25 January 2026 | 4 hours 27 minutes | Late-arriving aircraft |
| 22 July 2026 | 4 hours 27 minutes | National Airspace System |
Delay causes
Why OO 5861 runs late
Carrier accounts for 46% of the 10,000 delay minutes carriers reported here, and the remaining four split what is left.
- 46%Carrier
- 27%Late-arriving aircraft
- 18%National Airspace System
- 8%Extreme weather
- 0%Security
The largest share of delay minutes, 46%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 4,714 of the 10,000 delay minutes reported here. The split is drawn from 10,179 delay minutes reported on OO 5861.
Cancellations are rare at 0.29%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
15.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The same number turns up on one other city pair in the data, including TYS to DEN (16), but none flew often enough under OO 5861 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to COS only.
One caution: this is a thin sample. 347 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking OO 5861
For a booking, OO 5861 is a flight to put a long connection behind. 15.9% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- DEN to COS, every carrier and departure
- COS to DEN, the return direction
- SkyWest Airlines 5546 on the same route80.6%
- SkyWest Airlines 5246 on the same route84.3%
- SkyWest Airlines 4650 on the same route76.3%
- SkyWest Airlines 5306 on the same route83.6%
- Denver International (DEN) delay statistics
- SkyWest Airlines on-time record
- Every SkyWest Airlines flight number with a record
- The most and least reliable flight numbers in the US
- How often a connection fails at the major US hubs
A flight number here means SkyWest Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.