Flight profile · Delta Air Lines
DL1120
Seattle (SEA) to Salt Lake City (SLC) · scheduled 1:30 PM – 4:40 PM
How DL1120 performs
785 operations, June 2024 – July 2026.
DL1120 arrived on time 84.9% of the time, against 83.4% for all SEA → SLC flights, so this departure is 1.5 percentage points better than the route as a whole. Against Delta Air Lines’ own flights on this route it is 2.8 points worse.
Source: US DOT Bureau of Transportation Statistics · 785 operations, June 2024 – July 2026 · If DL1120 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where DL1120 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
Ask for the position of DL1120 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.
Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| DL1120 | 84.9% | 0.51% | -9 min | 3.9% | 785 |
| Delta Air Lines on SEA → SLC | 87.7% | 0.38% | -9 min | 3.3% | 6,823 |
| All SEA → SLC flights | 83.4% | 0.65% | -6 min | 3.9% | 12,345 |
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
Why DL1120 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for DL1120 on SEA → SLC. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies DL1120 comes in late, and what that does to the departure.
The aircraft flying DL1120 came in 15 or more minutes late on 14% of the departures where its previous flight is known. There are not enough departures in both groups to say how the flight left after a late one and after an on-time one.
Each departure is matched to the flight the same aircraft flew into SEA just before it, using the tail number in the DOT file, 747 of 781 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late |
|---|---|
| DL1120 | 14% |
| Network, same turn | 17% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often DL1120’s aircraft landed 15 or more minutes late is lower than the network’s. There are not enough departures in both groups to compare how it left.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
From pushback to gate
When it leaves SEA late, does that still matter by the time it reaches SLC?
DL1120 pushes back an average of 8.8 minutes late and reaches the gate at SLC an average of 0.4 minutes early. The 9.2 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 20.2 minutes on the taxiways at SEA, 1.1 minutes shorter than a typical SEA departure in the same hour.
On arrival at SLC, DL1120 spends 7.1 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is about what any arrival at SLC spends on the ground before reaching the gate.
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached SLC. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 29,480 departures from SEA scheduled in the clock hour DL1120 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at SLC (355,118 flights), not just DL1120’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
The hour it leaves SEA
Part of any flight’s record belongs to the clock rather than to the flight. DL1120 has one departure time, so this is what that time is worth.
On-time arrival rate. 29,480 departures from SEA are scheduled in the 1 PM–2 PM hour over the period, against 510,205 across the whole day.
DL1120 is scheduled out of SEA at 1:30 PM, in the 1 PM–2 PM bank. Departures from SEA in that hour arrive on time 76.9% of the time against 79.1% across the airport’s whole day, so the hour DL1120 leaves in is an ordinary one for SEA and explains nothing about its record either way.
The two airport figures cover every departure from SEA to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes DL1120 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| CHS→LGA Charleston to New York | May 7, 2024 – June 6, 2024 | 23 | — |
| BOI→SLC Boise to Salt Lake City | January 8, 2024 – May 6, 2024 | 120 | 90.0% |
| SLC→BOI Salt Lake City to Boise | January 8, 2024 – May 6, 2024 | 120 | 83.3% |
| MSN→DTW Madison to Detroit | December 16–31, 2023 | 16 | — |
| LAS→MSP Las Vegas to Minneapolis | September 5, 2023 – December 15, 2023 | 74 | — |
| MSP→LAS Minneapolis to Las Vegas | September 5, 2023 – December 15, 2023 | 74 | — |
| DEN→ATL Denver to Atlanta | October 9, 2023 – November 4, 2023 | 27 | — |
| MSP→SAV Minneapolis to Savannah | July 1, 2023 – September 3, 2023 | 30 | — |
| SAV→MSP Savannah to Minneapolis | July 1, 2023 – September 3, 2023 | 30 | — |
Because the same number has served different journeys, the statistics above describe only the route DL1120 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
23 min late
against a median of 9 min early
Percentiles over 785 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL1128 | Delta Air Lines | 93.0% | 15 min early | 849 |
| DL1016 | Delta Air Lines | 90.7% | 14 min early | 757 |
| AS630 | Alaska Airlines | 85.2% | 7 min early | 641 |
| DL1120 this flight | Delta Air Lines | 84.9% | 9 min early | 785 |
| DL1165 | Delta Air Lines | 80.2% | 3 min early | 721 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. DL1120 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 785 records of DL1120 operating SEA → SLC, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed