Airlines in Europe are trying to avoid a repeat of last summer’s travel chaos, when strikes and staff shortages were so bad that London’s Heathrow Airport capped passenger numbers and asked airlines to limit ticket sales. Travelers are going to jam European airports once again in July and August, with passenger numbers returning to or exceeding pre-pandemic levels.

To get a sense of how airports are handling the crush so far, passenger rights-company AirHelp analyzed delays of more than 15 minutes and cancelations in June at European airports with 5,000 or more flights that month. The worst offender was London’s Gatwick, with 54% of its flights meeting the company’s criteria for disruption, while Finland's Helsinki Airport ran the smoothest, with 18% of flights disrupted.

Some of Europe’s busiest airports landed in the middle. At Amsterdam’s Schiphol, which handled 72 million passengers in 2019, 36% of flights were affected, while Heathrow, which handled nearly 81 million passengers in 2019, had nearly 40% of flights off schedule.

Since late April, demand to Europe from US travelers has outpaced 2019 growth by as much as 20%, according to research from travel booking website Hopper. Prices are rising, too: Ticket prices to Europe from America are the highest in six years, the company says.

Spain in particular is seeing a surge of international tourism. It had 8.2 million visitors in May, an 18% increase from 2022 and 4% more than the same period in 2019, according to the country’s National Institute of Statistics. That’s a record high. So be prepared for long lines at airports—leave extra time on your next jaunt to the Balearics.

Good strategies to avoid travel meltdowns include: booking the first flight of the day; traveling on a Tuesday or Wednesday; and flying direct.

Read more: How to Navigate Summer Travel Chaos: Expert Time- and Money-Saving Tips

Here are the 10 airports in Europe that currently rank worst on those counts according to AirHelp—along with the 10 that are delivering a smoother summer.

10 Worst European Airports — Airports With Highest Percentage of Flight Disruptions

London Gatwick Airport (LGW)54.08% of flights disrupted

Lisbon Humberto Delgado Airport (LIS)51.04% of flights disrupted

Copenhagen Kastrup Airport (CPH)50.88% of flights disrupted

Paris Charles de Gaulle Airport (CDG)50.60% of flights disrupted

Antalya Airport (AYT)47.34% of flights disrupted

Istanbul Sabiha Gokcen (SAW)46.85% of flights disrupted

Rome Fiumicino Leonardo da Vinci Airport (FCO)44.05% of flights disrupted

Manchester International Airport (MAN)43.78% of flights disrupted

Milano Malpensa Airport (MXP)43.66% of flights disrupted

Frankfurt International Airport (FRA)42.99% of flights disrupted

10 Best European Airports — Airports With Lowest Percentage of Flight Disruptions

Helsinki-Vantaa Airport (HEL) 18.33% of flights disrupted

Dusseldorf International Airport (DUS)22.26% of flights disrupted

Oslo Gardermoen Airport (OSL)23.09% of flights disrupted

Warsaw Chopin Airport (WAW)23.35% of flights disrupted

Vienna International Airport (VIE)27.22% of flights disrupted

Madrid-Barajas International Airport (MAD)28.38% of flights disrupted

Barcelona-El Prat Airport (BCN)28.45% of flights disrupted

Stockholm Arlanda Airport (ARN)30.54% of flights disrupted

Istanbul Havalimani Airport (IST)32.15% of flights disrupted

Berlin Brandenburg Airport (BER)34.17% of flights disrupted