For all the marketing budgets London’s airports throw at convincing you they’re well-oiled machines, the most reliable UK airport for July travel isn’t any of them. It’s Belfast City.
A new analysis (by Locals Insider for our UK readers) of more than 700,000 UK flight departures across the past four Julys — drawing on Civil Aviation Authority data from 2022 through 2025 — has put one of the smallest airports in the country at the top of a 23-airport ranking.
Across the four-year period, just 29.2% of Belfast City’s July departures left more than 15 minutes late. That’s against 10,365 flights of real volume, not a small-sample quirk. And it’s a long way clear of any major hub.
By comparison, Heathrow — which handled more than 156,000 July departures in the same window — ran 40.7% of them late.
Gatwick, Britain’s second-busiest airport, managed 57.4%, meaning a coin flip would have given you better odds of an on-time July departure than checking the boarding gate.
What 700,000 flights tell us
The data is unambiguous on one front: Britain’s regional airports overwhelmingly outperform its major hubs in July. Aberdeen came in second at 30.1%, Liverpool John Lennon third at 30.6%, Exeter fourth at 31%, and Southampton fifth at 31.7%.
Five regional airports — none of them on most holidaymakers’ radar — occupy the top of the table. The pattern echoes what we found earlier this year when we ran the same analysis on Easter travel, where Belfast City also led the field alongside East Midlands and London City. The summer numbers are markedly worse across the board, though — peak July pressure on the bottom-third airports is meaningfully heavier than peak Easter.
Among London’s airports, London City was the best of a mediocre bunch at 38.6% — better than Heathrow, considerably better than Gatwick, but still nearly ten percentage points behind Belfast City.
Stansted ran 46.7% of its July flights late. Luton hit 48.2%. Gatwick’s 57.4% was the worst in the country, full stop.
The geographic spread of the top performers is interesting in itself. Belfast City, Aberdeen, Liverpool, Exeter and Southampton aren’t connected by airline, by ownership, or by route network. What they share is scale. None of them handles more than about 25,000 July departures across the four years studied.
Once a UK airport pushes past roughly 30,000 July movements, the delay rate climbs sharply — and the very busiest airports all sit in the bottom third of the table.
The worst performers
If Belfast City represents the upper bound of what’s currently possible at a UK airport in summer, three names mark the lower bound.
Gatwick ran 57.4% of its July flights late.
Manchester wasn’t far behind at 51.1%.
Edinburgh hit 50.3%. All three crossed the threshold most travellers would call a tipping point — when delays happen on more than half of departures, “late” stops being the exception and starts being the schedule.
Even Heathrow, which has invested heavily in punctuality programmes and operates as Britain’s flag-carrier hub, came in at 40.7% — nearly 12 percentage points worse than Belfast City. Its saving grace, if you do end up waiting, is that the airport hosts some of the best lounges in Europe, including Virgin Atlantic’s Clubhouse in Terminal 3.
Birmingham (47.3%) and Bristol (47.3%) sit in roughly the same band as the busiest London airports.
The pattern matters because peak summer is when the gap is widest. Air traffic control bottlenecks, weather disruption, knock-on effects from delayed inbound flights, ground-handling shortages — all of it compounds at scale, and all of it falls hardest on the airports with the least slack in the system.
Belfast City, with its single short runway and modest movement count, has the slack. Gatwick, scheduling near capacity through every daylight hour of July, doesn’t.
What this means if you’re flying in July
Belfast City Airport stands out as the strongest performer in our analysis by a clear margin. With fewer than three in ten July flights running late, it is delivering a level of summer punctuality that the UK’s major hub airports are a long way from matching. For passengers in Northern Ireland, the data is genuinely encouraging. While travellers at some of the country’s biggest airports are facing a near-coin-flip chance of a delay in July, Belfast City is offering a considerably more reliable experience — and that makes a real difference when you’re heading off on a summer holiday.
For most travellers, the practical takeaway isn’t to reroute through Belfast — geography and route networks usually decide your departure airport for you. But if you have any flexibility, the data argues strongly for the regional alternatives where they exist. A summer flight from Liverpool, Aberdeen, Southampton or East Midlands is statistically a markedly different experience from one out of Gatwick or Manchester.
The other practical takeaway is to set expectations honestly. If you’re flying from one of the bottom-third airports this July, a delay isn’t unusual — it’s the most likely outcome. Build it into your timings. Don’t book a ground transfer that assumes punctuality. Pack a charger. Install a real-time flight-tracking app — at busy airports, these often surface gate changes and delay notifications before the airline’s own app does.
It also pays to know your rights before you fly. UK and EU 261/2004 regulations mean delays of three hours or more on most routes trigger statutory compensation — and if you don’t fancy filing the paperwork yourself, no-win-no-fee claims companies will do it for you in exchange for a 20–35% cut of the payout. It’s also worth checking whether your travel insurance covers delays and missed connections — many policies do, but the trigger thresholds vary widely.
And if a regional airport is on offer for your route at a comparable fare, it’s worth a closer look.
UK Airport July Delays, 2022–25: The Full Ranking
| Rank | Airport | Total Flights | Delayed 15+ mins (%) |
|---|---|---|---|
| 1 | Belfast City | 10,365 | 29.2 |
| 2 | Aberdeen | 9,664 | 30.1 |
| 3 | Liverpool | 13,057 | 30.6 |
| 4 | Exeter | 2,782 | 31.0 |
| 5 | Southampton | 6,052 | 31.7 |
| 6 | East Midlands | 12,024 | 33.5 |
| 7 | Jersey | 6,965 | 34.7 |
| 8 | Leeds Bradford | 13,502 | 35.1 |
| 9 | Belfast International | 16,488 | 35.2 |
| 10 | Isle of Man | 3,197 | 35.5 |
| 11 | Glasgow | 24,534 | 36.3 |
| 12 | London City | 15,865 | 38.6 |
| 13 | Cardiff Wales | 3,374 | 38.8 |
| 14 | Heathrow | 156,140 | 40.7 |
| 15 | Bournemouth | 3,189 | 41.2 |
| 16 | Newcastle | 14,871 | 42.8 |
| 17 | Stansted | 64,228 | 46.7 |
| 18 | Birmingham | 32,792 | 47.3 |
| 19 | Bristol | 27,851 | 47.3 |
| 20 | Luton | 37,403 | 48.2 |
| 21 | Edinburgh | 41,570 | 50.3 |
| 22 | Manchester | 70,749 | 51.1 |
| 23 | Gatwick | 101,313 | 57.4 |
Source: Civil Aviation Authority. Methodology: analysis of CAA departure data for the months of July 2022, 2023, 2024 and 2025. Delay defined as departing 15 minutes or more after the scheduled time. Airports with insufficient July traffic in the period have been excluded from the ranking.
This analysis was conducted by Locals Insider in June 2026. Republication permitted with credit and link to Locals Insider.
