Flight number record
OO 4278
SkyWest Airlines · Detroit to Sault Ste. Marie
- Route
- DTW → CIU
- Departs
- 17:55
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 4278, 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 4278 sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land close to two hours behind schedule. That rests on 363 flights, with a median arrival 10 minutes early.
The national on-time rate over the same period is 77.3%, so OO 4278 runs 5 points behind the country as a whole. Across a thousand flights that is about 53 extra late arrivals.
Key figures
On time
72.0%
Arrivals under 15 minutes late, of 336 completed flights
Avg delay
117 min
Across delayed arrivals only, not all flights
Cancelled
6.89%
National rate is 1.89%
1 hour+ late
16.7%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. Beyond the headline rate, 16.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When OO 4278 flies
OO 4278 flies DTW to CIU without a single fixed slot. Its most common scheduled departure was 17:55, used on 130 of 363 flights, with 18:15 (92 flights) and 18:25 (62 flights) next.
- Departs 17:55130 flights35.8%
- Departs 18:1592 flights25.3%
- Departs 18:2562 flights17.1%
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 4278 runs 4 points better at 72.0%. 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 4278 next to DTW to CIU
Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 7 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 4278thin sample | 363 | 72.0% | 117 min | 6.89% | C− |
| All SkyWest Airlines on DTW–CIUthin sample | 363 | 72.0% | 117 min | 6.89% | C− |
| All carriers on DTW–CIUthin sample | 363 | 72.0% | 117 min | 6.89% | C− |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 4278 quarter by quarter
OO 4278 did not run the same all year. Its best quarter was Jul–Sep 2025 at 80.0% on time and its weakest Jan–Mar 2026 at 54.8%, a swing of 25 points on roughly 73 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 flights80.0%
- Oct–Dec 202590 flights79.3%
- Jan–Mar 202690 flights54.8%
- Apr–Jun 202691 flights77.9%
- Jul–Sep 202662 flights70.0%
Scale runs 45% to 85%.
By weekday, OO 4278 did best on Tuesday at 82.0% on time and worst on Sunday at 61.7%. Each day rests on about 52 flights, so a gap of 20 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 4278 runs when it is late
OO 4278 often beats the schedule: 125 of 336 completed flights, 37%, arrived 15 minutes or more early. When OO 4278 is late it tends to be very late: 56 of its 94 late arrivals were an hour or more behind, and 21 were two hours or more.
- 15+ min early125 flights37.2%
- Within 15 min117 flights34.8%
- 15–29 min late14 flights4.2%
- 30–59 min late24 flights7.1%
- 1–2 hours late35 flights10.4%
- 2+ hours late21 flights6.3%
Scale runs 0% to 100%.
Share of 336 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 91 departures that left 15 minutes late or more, only 5 made it up before arrival. 8 flights left on time and still arrived late.
The worst days
Worst days for OO 4278
The latest arrival of the period was on 8 July 2026, 17 hours 50 minutes behind schedule; most of its delay minutes were filed as extreme weather. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 8 July 2026 | 17 hours 50 minutes | Extreme weather |
| 11 February 2026 | 15 hours 59 minutes | Carrier |
| 24 March 2026 | 13 hours 49 minutes | Carrier |
| 19 May 2026 | 5 hours 50 minutes | Carrier |
| 23 January 2026 | 5 hours 45 minutes | Carrier |
Delay causes
Why OO 4278 runs late
Carrier accounts for 71% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 71%Carrier
- 24%Extreme weather
- 5%National Airspace System
Extreme weather accounts for 24% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 4.1 times the usual weather exposure. The split is drawn from 10,991 delay minutes reported on OO 4278.
Cancellations run at 6.89%, against 1.89% nationally. That is about one flight in fifteen cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
16.7% 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.
Every one of the 363 flights under OO 4278 in the data flew DTW to CIU. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 363 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 4278
For a booking, the cancellation rate is the figure to plan around on OO 4278: 6.89% of its 363 scheduled flights did not operate. A late arrival costs close to two hours, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- Detroit Metropolitan Wayne County (DTW) 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.