Flight number record

OO 3900

SkyWest Airlines · Detroit to South Bend

Route: DTW → SBN
Departs: 19:45
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 late.

The national on-time rate over the same period is 77.6%, so OO 3900 runs 16 points behind the country as a whole. Across a thousand flights that is about 156 extra late arrivals.

On time

62.0%

Arrivals under 15 minutes late, of 361 completed flights

Avg delay

108 min

Across delayed arrivals only, not all flights

Cancelled

1.10%

National rate is 1.81%

1 hour+ late

21.6%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. Beyond the headline rate, 21.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

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 337 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 19:45337 flights92.3%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 68.2%, and OO 3900 runs 6 points worse at 62.0%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

OO 3900 next to DTW to SBN

Every carrier on DTW to SBN combined arrived on time 70.4% 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 70.3% on time. Across its whole network SkyWest Airlines managed 79.0%, which this flight trails by 17 points.

OO 3900 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
OO 3900	365	62.0%	108 min	1.10%	D
All SkyWest Airlines on DTW–SBN	711	70.3%	101 min	0.98%	C+
All carriers on DTW–SBN	712	70.4%	101 min	0.98%	C+
SkyWest Airlines, whole network	852,935	79.0%	88 min	1.77%	B

Across the year

OO 3900 quarter by quarter

OO 3900 did not run the same all year. Its best quarter was Apr–Jun 2026 at 71.4% on time and its weakest Jan–Mar 2026 at 48.3%, a swing of 23 points on roughly 91 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 202592 flights60.9%
Oct–Dec 202592 flights67.0%
Jan–Mar 202690 flights48.3%
Apr–Jun 202691 flights71.4%

Scale runs 40% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, OO 3900 did best on Saturday at 78.0% on time and worst on Monday at 50.0%. Each day rests on about 52 flights, so a gap of 28 points is worth noticing but could still narrow in another year.

Delay causes

Why OO 3900 runs late

One category carries most of the weight here. Carrier accounts for 71% of the 15,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
71%
Extreme weather
21%
National Airspace System
8%

Extreme weather accounts for 21% 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 3.3 times the usual weather exposure. The split is drawn from 14,849 delay minutes reported on OO 3900.

Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 21.6% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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. 21.6% 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.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures