Catania airport's operator cancelled at least 45 flights due to the risk posed by falling ash. Flights were suspended until 8pm local time, the airport said on its website.
Earlier on Monday, it had said departures and arrivals had been halted until just 1pm.
Ryanair said on Monday that flights to and from Catania could be delayed, diverted or cancelled because of the volcanic eruption.
Wizz said the activity has meant four rotations have been impacted by delays or cancellations and there could be further changes if the volcano continues to erupt.
The status of the British Airways flight from London Gatwick Airport to Catania on Monday morning was delayed. easyJet also delayed some flights from London to Catania.
Catania's Mayor Enrico Trantino has also prohibited the use of motorcycles and bicycles for the next 48 hours, “because several areas are covered with a layer of volcanic ash”.
The ash can quickly become slippery on roads and increase the risk of accidents.
At 3,324 metres, Etna is the tallest active volcano in Europe and has erupted frequently in the past 500,000 years.
Most recently, Catania airport was closed for a day on May 21 due to an eruption.
Around 10 million passengers last year transited through the airport, which serves the eastern part of Sicily.