Flight number record
OO 3900
SkyWest Airlines · Detroit to South Bend
- Route
- DTW → SBN
- Departs
- 19:45
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s OO 3900, 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 3900 draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 365 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.3%, so OO 3900 runs 14 points behind the country as a whole. Across a thousand flights that is about 139 extra late arrivals.
Key figures
On time
63.4%
Arrivals under 15 minutes late, of 361 completed flights
Avg delay
111 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.89%
1 hour+ late
20.5%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. Beyond the headline rate, 20.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When OO 3900 flies
OO 3900 is scheduled to leave Detroit (DTW) at 19:45 local time and reach South Bend (SBN) at 20:48. That slot held for 346 of the 365 scheduled departures in the data, so the figures below describe one steady operation rather than a number that moved around the clock.
- Departs 19:45346 flights94.8%
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 19:45 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and OO 3900 runs 5 points worse at 63.4%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
OO 3900 next to DTW to SBN
Every carrier on DTW to SBN combined arrived on time 71.1% of the time across 712 flights, so OO 3900 is 8 points behind it. SkyWest flew 711 flights on the same city pair under all its flight numbers, including this one, and those ran 71.0% on time. Across its whole network SkyWest Airlines managed 78.7%, which this flight trails by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| OO 3900 | 365 | 63.4% | 111 min | 1.10% | D |
| All SkyWest Airlines on DTW–SBN | 711 | 71.0% | 104 min | 0.98% | C+ |
| All carriers on DTW–SBN | 712 | 71.1% | 104 min | 0.98% | C+ |
| SkyWest Airlines, whole network | 855,406 | 78.7% | 88 min | 1.79% | B |
Across the year
OO 3900 quarter by quarter
OO 3900 did not run the same all year. Its best quarter was Jul–Sep 2025 at 73.3% on time and its weakest Jan–Mar 2026 at 48.3%, 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 flights73.3%
- Oct–Dec 202592 flights67.0%
- Jan–Mar 202690 flights48.3%
- Apr–Jun 202691 flights71.4%
- Jul–Sep 202662 flights62.9%
Scale runs 40% to 80%.
By weekday, OO 3900 did best on Saturday at 78.0% on time and worst on Monday at 56.6%. Each day rests on about 52 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late OO 3900 runs when it is late
OO 3900 often beats the schedule: 94 of 361 completed flights, 26%, arrived 15 minutes or more early. When OO 3900 is late it tends to be very late: 74 of its 132 late arrivals were an hour or more behind, and 38 were two hours or more.
- 15+ min early94 flights26.0%
- Within 15 min135 flights37.4%
- 15–29 min late25 flights6.9%
- 30–59 min late33 flights9.1%
- 1–2 hours late36 flights10.0%
- 2+ hours late38 flights10.5%
Scale runs 0% to 100%.
Share of 361 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 133 departures that left 15 minutes late or more, only 12 made it up before arrival. 11 flights left on time and still arrived late.
The worst days
Worst days for OO 3900
The latest arrival of the period was on 1 December 2025, 13 hours 42 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 December 2025 | 13 hours 42 minutes | Carrier |
| 22 January 2026 | 12 hours 53 minutes | Carrier |
| 22 July 2026 | 10 hours 46 minutes | Carrier |
| 17 March 2026 | 7 hours 8 minutes | Carrier |
| 5 December 2025 | 6 hours 39 minutes | Carrier |
Delay causes
Why OO 3900 runs late
Carrier accounts for 74% of the 15,000 delay minutes carriers reported here, and the remaining four split what is left.
- 74%Carrier
- 19%Extreme weather
- 8%National Airspace System
Extreme weather accounts for 19% 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 3.1 times the usual weather exposure. The split is drawn from 14,581 delay minutes reported on OO 3900.
Cancellations sit at 1.10% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
20.5% 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 365 flights under OO 3900 in the data flew DTW to SBN. 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. 365 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 3900
For a booking, OO 3900 is a flight to put a long connection behind. 20.5% 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
- 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.