Flight number record
UA 1220
United Airlines · Denver to Detroit
- Route
- DEN → DTW
- Departs
- 17:40
- Flights
- 328
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1220, check with United Airlines.
UA 1220 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 328 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.6%, so UA 1220 runs 9 points behind the country as a whole. Across a thousand flights that is about 90 extra late arrivals.
Key figures
On time
68.6%
Arrivals under 15 minutes late, of 328 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
1 hour+ late
11.3%
National rate is 8.1%
These figures cover 328 flights between July 2025 and June 2026. Beyond the headline rate, 11.3% 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 UA 1220 flies
UA 1220 flies DEN to DTW without a single fixed slot. Its most common scheduled departure was 17:40, used on 53 of 328 flights, with 17:20 (49 flights) and 17:47 (41 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 17:4053 flights16.2%
- Departs 17:2049 flights14.9%
- Departs 17:4741 flights12.5%
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 17:40 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and UA 1220 runs level with that at 68.6%. 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
UA 1220 next to DEN to DTW
Every carrier on DEN to DTW combined arrived on time 77.6% of the time across 3,088 flights, so UA 1220 is 9 points behind it. United flew 727 flights on the same city pair under all its flight numbers, including this one, and those ran 79.7% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| UA 1220thin sample | 328 | 68.6% | 66 min | 0.00% | C+ |
| All United Airlines on DEN–DTW | 727 | 79.7% | 60 min | 0.00% | B+ |
| All carriers on DEN–DTW | 3,088 | 77.6% | 61 min | 0.45% | B+ |
| United Airlines, whole network | 821,041 | 79.0% | 72 min | 1.01% | B |
Across the year
UA 1220 quarter by quarter
Quarter by quarter UA 1220 held fairly steady: 64.1% in Jul–Sep 2025, 72.7% in Oct–Dec 2025, 73.3% in Jan–Mar 2026 and 65.9% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202592 flights64.1%
- Oct–Dec 202555 flights72.7%
- Jan–Mar 202690 flights73.3%
- Apr–Jun 202691 flights65.9%
Scale runs 55% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, UA 1220 did best on Saturday at 74.5% on time and worst on Friday at 61.7%. Each day rests on about 47 flights, so a gap of 13 points is worth noticing but could still narrow in another year.
Delay causes
Why UA 1220 runs late
One category carries most of the weight here. Late-arriving aircraft accounts for 51% of the 6,784 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.
- 51%Late-arriving aircraft
- 25%Carrier
- 21%National Airspace System
- 2%Extreme weather
- 1%Security
51% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 6,784 reported delay minutes here, that single category outweighs weather by 31 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 6,784 delay minutes reported on UA 1220.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
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. 11.3% 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.
The 1,123 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The same number turns up on five other city pairs in the data, including BWI to LAX (37), LAS to DEN (31) and SFO to LAS (31), but none flew often enough under UA 1220 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to DEN to DTW only.
One caution: this is a thin sample. 328 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 UA 1220
For a booking, UA 1220 is one of the weaker ways to fly DEN to DTW: 9 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- DEN to DTW, every carrier and departure
- DTW to DEN, the return direction
- Delta Air Lines 1745 on the same route89.5%
- Delta Air Lines 2787 on the same route81.7%
- Denver International (DEN) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- United Airlines on-time record
- Every United Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means United 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.