Flight profile · Delta Air Lines
DL2021
Miami (MIA) to Salt Lake City (SLC) · scheduled 6:40 PM – 10:10 AM
How DL2021 performs
784 operations, June 2024 – July 2026.
Source: US DOT Bureau of Transportation Statistics · 784 operations, June 2024 – July 2026 · If DL2021 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where DL2021 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 DL2021 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 |
|---|---|---|---|---|---|
| DL2021 | 73.8% | 0.64% | -2 min | 8.6% | 784 |
| Delta Air Lines on MIA → SLC | 73.0% | 0.44% | -1 min | 9.2% | 1,126 |
| All MIA → SLC flights | 74.1% | 0.59% | -3 min | 8.8% | 2,045 |
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
Why DL2021 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 DL2021 on MIA → 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 DL2021 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, DL2021 pushed back an average of 67 minutes late; when it came in on time or early, an average of 6 minutes late.
Each departure is matched to the flight the same aircraft flew into MIA just before it, using the tail number in the DOT file, 762 of 779 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 | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| DL2021 | 18% | 84% | 15% |
| Network, same turn | 17% | 68% | 9% |
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 DL2021’s aircraft landed 15 or more minutes late is about the same as the network’s and, once the aircraft was late, how often DL2021 left 15 or more minutes late is higher than the network’s.
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 MIA late, does that still matter by the time it reaches SLC?
DL2021 pushes back an average of 18.7 minutes late and reaches the gate at SLC an average of 13.2 minutes late. The 5.4 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 24.4 minutes on the taxiways at MIA, 1.3 minutes longer than a typical MIA departure in the same hour.
On arrival at SLC, DL2021 spends 8.0 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 19,684 departures from MIA scheduled in the clock hour DL2021 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 DL2021’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · June 2024 – July 2026
The hour it leaves MIA
Part of any flight’s record belongs to the clock rather than to the flight. DL2021 has one departure time, so this is what that time is worth.
On-time arrival rate. 19,684 departures from MIA are scheduled in the 6 PM–7 PM hour over the period, against 340,469 across the whole day.
DL2021 is scheduled out of MIA at 6:40 PM, in the 6 PM–7 PM bank. Departures from MIA in that hour arrive on time 63.2% of the time against 73.2% across the airport’s whole day — the slot alone is worth 9.9 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from MIA 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 DL2021 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 |
|---|---|---|---|
| LAS→LAX Las Vegas to Los Angeles | May 7, 2024 – June 6, 2024 | 31 | — |
| LAX→LAS Los Angeles to Las Vegas | May 7, 2024 – June 6, 2024 | 31 | — |
| CVG→MCO Cincinnati / Covington to Orlando | April 9, 2024 – May 6, 2024 | 28 | — |
| ATL→JFK Atlanta to New York | March 10, 2024 – April 8, 2024 | 30 | — |
| MCO→ATL Orlando to Atlanta | January 8, 2024 – March 9, 2024 | 59 | — |
| MSP→MEM Minneapolis to Memphis | December 24, 2023 – January 6, 2024 | 5 | — |
| DTW→PVD Detroit to Providence/Warwick | December 16–21, 2023 | 6 | — |
| ATL→MEM Atlanta to Memphis | September 10, 2023 – December 15, 2023 | 86 | — |
| MEM→ATL Memphis to Atlanta | September 10, 2023 – December 15, 2023 | 84 | — |
| DTW→IAD Detroit to Washington | November 4, 2023 | 1 | — |
| ATL→BUF Atlanta to Buffalo | July 10, 2023 – September 4, 2023 | 46 | — |
| BUF→ATL Buffalo to Atlanta | July 10, 2023 – September 4, 2023 | 46 | — |
| MSP→ORD Minneapolis to Chicago | July 2–9, 2023 | 7 | — |
Because the same number has served different journeys, the statistics above describe only the route DL2021 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.
50 min late
against a median of 2 min early
Percentiles over 784 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering June 2024 – July 2026
Data and methodology
Calculated by FlyerIntel from 784 records of DL2021 operating MIA → 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