How often are these flights late or cancelled?
Delta Airlines
In the twelve months from July 2025 to June 2026, 22.9% of 4,293 movements arriving into the UK were disrupted — more than fifteen minutes late or cancelled at short notice.
Put the other way round, 77.1% of 4,293 movements met the fifteen-minute convention. These are historical observations, not a forecast.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Source: CAA punctuality statistics · snapshot 17/08/2026 10:24 · method route-record-v2.1 · Versioned claims, formulas and entity mapping.
0 operations (0.00%) excluded because their published percentages could not be reconciled to whole numbers. Excluded operations enter neither the numerator nor the denominator. Outcome figures and comparisons are unavailable when the excluded share exceeds fifteen percent.
The four numbers at a glance
22.9% of 4,293 movements were disrupted over July 2025 to June 2026.
Average delay covers delayed movements only. Its range reflects rounded source means and the unknown count of exactly punctual movements.
| Disruption | Short-notice cancellations | Delay among delayed movements | Over three hours |
|---|---|---|---|
| 22.9% of 4,293 movements | 1.2% of 4,293 movements | 33.7–66.4 minutes; delayed denominator 933–1,713 | 1.0% of 4,293 movements |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
When late, how late?
1.0% of 4,293 movements passed the three-hour mark.
The ladder shows how many movements crossed each threshold. Cancellations are separate: 1.2% of 4,293 movements.
| Delay | Share and sample | One event per movements |
|---|---|---|
| More than 15 minutes | 21.7% of 4,293 movements | 4.6 |
| More than 30 minutes | 13.4% of 4,293 movements | 7.5 |
| More than 60 minutes | 6.7% of 4,293 movements | 15.0 |
| More than 120 minutes | 2.4% of 4,293 movements | 42.5 |
| More than 180 minutes | 1.0% of 4,293 movements | 99.8 |
| More than 360 minutes | 0.1% of 4,293 movements | 1,431.0 |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Slightly late or occasionally a disaster?
2.4% of 4,293 movements passed two hours.
The histogram shows the published delay bands. Bucket shares use all reported operations, including unmatched records; cancellations are reported separately.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Better or worse since the start of the archive?
Best month: Sep 2020, 5.2% of 58 movements. Worst month: Aug 2021, 55.6% of 54 movements.
The line traces every month. Lower disruption is better; gaps are never zeros. Pandemic readings describe a different operating regime.
Every monthly observation
| Month | Disruption on arrivals |
|---|---|
| Jan 2018 | 22.3% of 345 movements |
| Feb 2018 | 17.7% of 277 movements |
| Mar 2018 | 30.3% of 287 movements |
| Apr 2018 | 18.8% of 272 movements |
| May 2018 | 21.7% of 309 movements |
| Jun 2018 | 31.5% of 330 movements |
| Jul 2018 | 29.2% of 343 movements |
| Aug 2018 | 24.0% of 341 movements |
| Sep 2018 | 14.2% of 317 movements |
| Oct 2018 | 11.4% of 280 movements |
| Nov 2018 | 22.6% of 248 movements |
| Dec 2018 | 18.3% of 268 movements |
| Jan 2019 | 17.1% of 252 movements |
| Feb 2019 | 18.9% of 190 movements |
| Mar 2019 | 13.0% of 253 movements |
| Apr 2019 | 15.5% of 277 movements |
| May 2019 | 19.2% of 344 movements |
| Jun 2019 | 35.1% of 390 movements |
| Jul 2019 | 29.7% of 407 movements |
| Aug 2019 | 30.8% of 406 movements |
| Sep 2019 | 20.7% of 363 movements |
| Oct 2019 | 19.7% of 320 movements |
| Nov 2019 | 11.5% of 269 movements |
| Dec 2019 | 20.8% of 274 movements |
| Jan 2020 | 14.2% of 261 movements |
| Feb 2020 | 13.1% of 245 movements |
| Mar 2020 | 8.8% of 171 movements |
| Apr 2020 | suppressed: fewer than twenty movements |
| May 2020 | suppressed: fewer than twenty movements |
| Jun 2020 | no events in 23 movements — small sample, not ranked |
| Jul 2020 | 31.8% of 22 movements — small sample, not ranked |
| Aug 2020 | 17.0% of 47 movements — small sample, not ranked |
| Sep 2020 | 5.2% of 58 movements |
| Oct 2020 | 9.6% of 73 movements |
| Nov 2020 | 18.3% of 60 movements |
| Dec 2020 | 39.3% of 61 movements |
| Jan 2021 | 16.3% of 49 movements — small sample, not ranked |
| Feb 2021 | 20.0% of 40 movements — small sample, not ranked |
| Mar 2021 | 14.3% of 63 movements |
| Apr 2021 | 12.3% of 73 movements |
| May 2021 | 13.2% of 76 movements |
| Jun 2021 | 19.7% of 66 movements |
| Jul 2021 | 50.0% of 56 movements |
| Aug 2021 | 55.6% of 54 movements |
| Sep 2021 | 14.3% of 56 movements |
| Oct 2021 | 18.7% of 75 movements |
| Nov 2021 | 33.3% of 102 movements |
| Dec 2021 | 28.3% of 120 movements |
| Jan 2022 | 19.4% of 124 movements |
| Feb 2022 | 15.7% of 89 movements |
| Mar 2022 | 40.4% of 99 movements |
| Apr 2022 | 30.1% of 166 movements |
| May 2022 | 30.3% of 304 movements |
| Jun 2022 | 50.1% of 345 movements |
| Jul 2022 | 38.0% of 358 movements |
| Aug 2022 | 28.6% of 343 movements |
| Sep 2022 | 31.1% of 312 movements |
| Oct 2022 | 28.0% of 296 movements |
| Nov 2022 | 14.8% of 271 movements |
| Dec 2022 | 48.5% of 268 movements |
| Jan 2023 | 31.5% of 276 movements |
| Feb 2023 | 25.0% of 248 movements |
| Mar 2023 | 31.6% of 301 movements |
| Apr 2023 | 30.3% of 360 movements |
| May 2023 | 36.1% of 424 movements |
| Jun 2023 | 44.3% of 445 movements |
| Jul 2023 | 32.6% of 460 movements |
| Aug 2023 | 34.3% of 460 movements |
| Sep 2023 | 33.4% of 416 movements |
| Oct 2023 | 26.1% of 421 movements |
| Nov 2023 | 20.7% of 343 movements |
| Dec 2023 | 24.4% of 357 movements |
| Jan 2024 | 35.0% of 309 movements |
| Feb 2024 | 18.5% of 270 movements |
| Mar 2024 | 21.9% of 324 movements |
| Apr 2024 | 19.3% of 342 movements |
| May 2024 | 23.8% of 395 movements |
| Jun 2024 | 25.4% of 414 movements |
| Jul 2024 | 32.6% of 427 movements |
| Aug 2024 | 24.6% of 427 movements |
| Sep 2024 | 25.5% of 415 movements |
| Oct 2024 | 21.0% of 386 movements |
| Nov 2024 | 29.4% of 296 movements |
| Dec 2024 | 36.5% of 323 movements |
| Jan 2025 | 32.4% of 306 movements |
| Feb 2025 | 23.4% of 265 movements |
| Mar 2025 | 25.9% of 316 movements |
| Apr 2025 | 21.9% of 333 movements |
| May 2025 | 22.5% of 395 movements |
| Jun 2025 | 25.0% of 424 movements |
| Jul 2025 | 26.6% of 440 movements |
| Aug 2025 | 25.4% of 445 movements |
| Sep 2025 | 15.4% of 402 movements |
| Oct 2025 | 27.3% of 377 movements |
| Nov 2025 | 25.3% of 308 movements |
| Dec 2025 | 36.9% of 320 movements |
| Jan 2026 | 29.6% of 304 movements |
| Feb 2026 | 25.3% of 273 movements |
| Mar 2026 | 12.9% of 318 movements |
| Apr 2026 | 12.9% of 333 movements |
| May 2026 | 15.5% of 387 movements |
| Jun 2026 | 23.3% of 386 movements |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
What did the big disruptions do here?
Each event is compared with the twelve preceding calendar months and the first later return to baseline.
A worse month is not proof the named event caused it. The open data carry no delay-cause field. Recovery is observed for at most eight subsequent months.
| Event | Direction | Disruption that month | Baseline before | Return to baseline |
|---|---|---|---|---|
| Pandemic regime · Jun 2020 | Arrivals | no events in 23 movements — small sample, not ranked | no complete baseline | not enough data: needs a complete baseline and a publishable event month |
| Pandemic regime · Jun 2020 | Departures | 4.3% of 23 movements — small sample, not ranked | no complete baseline | not enough data: needs a complete baseline and a publishable event month |
| Summer 2022 breakdown · Jul 2022 | Arrivals | 38.0% of 358 movements | 32.2% across 1,590 flights | returned the next month |
| Summer 2022 breakdown · Jul 2022 | Departures | 63.4% of 358 movements | 23.2% across 1,591 flights | returned after 3 months |
| NATS system failure · Aug 2023 | Arrivals | 34.3% of 460 movements | 31.9% across 4,004 flights | returned after 2 months |
| NATS system failure · Aug 2023 | Departures | 31.9% of 464 movements | 23.4% across 4,012 flights | returned the next month |
| Heathrow fire closure · Mar 2025 | Arrivals | 25.9% of 316 movements | 26.3% across 4,320 flights | returned the next month |
| Heathrow fire closure · Mar 2025 | Departures | 21.5% of 316 movements | 19.2% across 4,329 flights | returned the next month |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Which time of year has been hardest?
Highest median: Jun, 31.5% across 7 months. Lowest median: Feb, 18.9% across 7 months.
Even the same calendar month differs across years. This is a record, not a forecast; pandemic years are excluded from the summaries.
Each cell is one calendar month of one year; the number is the share of that month’s arrivals that were disrupted. Darker means worse. A blank cell means no published data, not zero.
Month-by-month table: median, observed range and sample
| Month | Median | Observed range | Sample |
|---|---|---|---|
| Jan | 29.6% | 17.1–35.0% | 7 months, 1,916 flights |
| Feb | 18.9% | 15.7–25.3% | 7 months, 1,612 flights |
| Mar | 25.9% | 12.9–40.4% | 7 months, 1,898 flights |
| Apr | 19.3% | 12.9–30.3% | 7 months, 2,083 flights |
| May | 22.5% | 15.5–36.1% | 7 months, 2,558 flights |
| Jun | 31.5% | 23.3–50.1% | 7 months, 2,734 flights |
| Jul | 31.1% | 26.6–38.0% | 6 months, 2,435 flights |
| Aug | 27.0% | 24.0–34.3% | 6 months, 2,422 flights |
| Sep | 23.1% | 14.2–33.4% | 6 months, 2,225 flights |
| Oct | 23.6% | 11.4–28.0% | 6 months, 2,080 flights |
| Nov | 21.6% | 11.5–29.4% | 6 months, 1,735 flights |
| Dec | 30.5% | 18.3–48.5% | 6 months, 1,810 flights |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Which routes have the best and worst record?
Lowest disruption: EDI ↔ BOSTON, 18.1% of 171 movements. Highest disruption: LGW ↔ NEW-YORK-JF-KENNEDY, 34.3% of 70 movements.
The airline table uses this carrier on each route; airport and country tables combine carriers. Each figure is arrivals into its UK airport. Only sufficiently large exact samples enter the ordered comparison.
All route comparisons and sample flags
| Route | Disruption | Cancellations | Sample flag |
|---|---|---|---|
| EDI ↔ BOSTON | 18.1% of 171 movements | no events in 171 movements | descriptive comparison |
| Heathrow ↔ Boston | 18.6% of 366 movements | 0.8% of 366 movements | descriptive comparison |
| LHR ↔ MINNEAPOLIS-ST-PAUL | 18.6% of 366 movements | 0.3% of 366 movements | descriptive comparison |
| Heathrow ↔ Atlanta | 21.5% of 1,098 movements | 1.1% of 1,098 movements | descriptive comparison |
| Heathrow ↔ Seattle (Tacoma) | 22.4% of 366 movements | 1.1% of 366 movements | descriptive comparison |
| LHR ↔ SALT-LAKE-CITY | 23.1% of 264 movements | 4.2% of 264 movements | descriptive comparison |
| Edinburgh ↔ New York (Jf Kennedy) | 25.0% of 264 movements | 0.4% of 264 movements | descriptive comparison |
| LHR ↔ DETROIT | 25.1% of 367 movements | 0.3% of 367 movements | descriptive comparison |
| Heathrow ↔ New York (Jf Kennedy) | 26.5% of 733 movements | 1.9% of 733 movements | descriptive comparison |
| EDI ↔ ATLANTA | 26.8% of 224 movements | 1.3% of 224 movements | descriptive comparison |
| LGW ↔ NEW-YORK-JF-KENNEDY | 34.3% of 70 movements | 1.4% of 70 movements | descriptive comparison |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Which UK airports appear in this record?
3 published groups have enough arrivals to describe.
These operations are not matched for season, aircraft or time of day. The table makes no causal comparison.
| UK airport | Disruption | Sample flag |
|---|---|---|
| Edinburgh | 23.9% of 660 movements | descriptive comparison |
| Gatwick | 34.3% of 70 movements | descriptive comparison |
| Heathrow | 22.5% of 3,563 movements | descriptive comparison |
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Arrivals vs departures
22.9% of 4,293 movements arrivals were disrupted, against 18.6% of 4,294 movements departures.
The directions have separate denominators. A departure delay does not establish late arrival at the final destination; legal conditions differ by direction and carrier.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Movements past the three-hour mark
1.0% of 4,293 movements were more than three hours late over July 2025 to June 2026.
Cancellation is counted separately and is not a three-hour delay. Monthly counts cannot establish a passenger claim.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Facts about this record
Delta Airlines appears from Jan 2018 to Jun 2026 with 27,370 arrivals.
The bounds describe the published record, not every commercial service. Final point is not necessarily a nonstop destination.
Archive route pairs: 47.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
What this data cannot tell you
Delay cause, individual passenger experience, commercial decisions and future performance are not established here.
Also absent are aircraft type, within-month time-of-day splits and cancellations made ahead of the short-notice reporting window.
0 operations (0.00%) excluded because their published percentages could not be reconciled to whole numbers. Excluded operations enter neither the numerator nor the denominator. Outcome figures and comparisons are unavailable when the excluded share exceeds fifteen percent.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Quick answers
These answers use the same populations and window as the tables above.
Every percentage retains its denominator.
How disrupted are these arrivals?
22.9% of 4,293 movements over July 2025 to June 2026.
How often are they cancelled?
1.2% of 4,293 movements at short notice.
How late is late?
33.7–66.4 minutes; delayed denominator 933–1,713
Are services improving?
The monthly line records past changes; it is not a forecast or a causal comparison.
Which routes are compared?
The route table uses separately identified UK airport and final-point pairs, with small samples flagged.
Does this cover my flight?
Only published aggregate movements; the circumstances of any individual flight are unknown.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
How this was calculated
Source: CAA punctuality statistics · snapshot 17/08/2026 10:24 · method route-record-v2.1 · Versioned claims, formulas and entity mapping.
Integer bucket counts are recovered from rounding intervals over D=M+C+U with their sum constrained to M. Ambiguous counts remain ranges; failed reconciliation is quarantined.
Definitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.
Your trip has already gone wrong
The monthly line and events table show whether your month was typical or unusual in the published record.
Nothing here decides an individual case or what a passenger may be owed.
CAA: the official route to complainDefinitions, denominators and limits
Arrivals into UK reporting airports only unless labelled departures. Denominator: operated movements plus short-notice cancellations (M+C). A movement is not a scheduled flight. Unmatched records are data quality, not outcomes. Cells below twenty movements are suppressed; twenty to forty-nine are descriptive and not ranked.