NEW YORK • At London Heathrow, the chaos has gotten so intense — between the interminable security queues, rampant flight delays and cancellations, and too few luggage handlers to match travellers with their bags — that the airport has taken the drastic move of limiting airline ticket sales until it can get its act together.

It may be the most prominent example of airport dysfunction in this summer of travel hell, but it’s hardly the worst.

According to newly released data from Hopper Inc, the Goldman Sachs-backed online travel agency whose roots are in aviation and big data, Heathrow doesn’t even rank among Europe’s worst 10 airports for delays this month. It falls 15th on that list, with an average of 51% of its flights being delayed since the beginning of July.

The site’s data is collected via Official Aviation Guide, a leading provider of digital flight information and analytics for airports, airlines and travel tech companies, for the purpose of keeping customers informed about disruptions on their booked routes. The figures, which reflect a three-day lag, are more current than any public data source.

Here are the 10 airports that currently rank worst for delays according to Hopper (see graphic) — along with the 10 airports that are actually pulling off a relatively smooth summer of on-time performance.

And while it’s true that the worst offenders all underperform compared to Heathrow, a Hopper spokesperson offers the following context: “On a volume basis, London Heathrow is much larger than most airports and our ranking is based on percentage of delays, not number of people impacted.”

Similarly, the figures are averages for the first nine days of July; on its worst travel days, Heathrow’s delays hit 62% of flights, which would have landed it right on the bottom 10 list, and with exponentially thousands more travellers impacted.

In other words, don’t take the data in absolute terms — but do be warned that delays likely lie ahead. If your travel plans are flexible, it might be worth looking into a rebook to minimise the risk. — Bloomberg / Pic by Bloomberg