Tens of thousands of travellers due to fly to or from airports in eastern Sicily have seen their flights diverted or cancelled due to the eruption of Etna.
An ash plume from the 3,357m volcano spread across eastern part of the island.
Catania airport, which normally handles around 200 flights each day in August, closed after the arrival of a flight from Casablanca at 2.38am local time on Monday.
The airport, which is the main entry point to Sicily, is about 50km south of Etna.
The 6.30am easyJet flight from London Gatwick to Catania is currently being held on the ground at the Sussex airport, with an estimated arrival time of 8pm – over nine hours behind schedule.
The airline told passengers: “We’re sorry that your flight has been delayed. This is because volcanic activity in Catania is causing restrictions to the areas in which aircraft are permitted to fly.
“The safety of you and our crew is our highest priority and we thank you for your patience.”
British Airways had a 7.10am departure from Gatwick to Catania, which is also showing a delay of nine hours.
Seven Ryanair flights due to land at Catania on Monday morning have been diverted to Trapani airport at the far west of Sicily.
The carrier told travellers: “Due to the eruption of Mount Etna, we would like to advise all passengers traveling to and from Catania on 14 August of possible delays, diversion or cancellations to flights.
“Affected passengers will be notified as soon as possible
“Ryanair apologises for the disruptions caused by this volcanic eruption which is outside of our control.”
Dozens of other flights have been cancelled, including at least 10 ITA flights between Rome and Catania.
The morning wave of departures from Catania was due to begin at 6am, with all 10 flights in the first hour cancelled.
Later flights are scheduled from Catania to Bristol, Edinburgh, Gatwick (two departures) and Luton on easyJet, as well as BA and Wizz Air flights to Gatwick. In total, over 1,000 passengers are due to fly back from the Italian island on Monday.
Catania airport was temporarily closed between mid-July and early August because of fire damage.
Comiso airport, which is around 150km from Etna, is currently closed with flights intended to arrive there showing delays of several hours.
Under European air passengers’ rights rules, travellers whose flights are heavily delayed or cancelled are entitled to hotels and meals as appropriate.
In 2010 the eruption of an Icelandic volcano brought aviation in northern Europe to a halt for almost a week.