Rising tensions in the Middle East have created air travel chaos, with global airlines diverting or cancelling flights on Wednesday and regional airports, including Lebanon, Israel and Kuwait, showing long delays, according to FlightRadar24 data.

Concern over travel disruption as the conflict intensifies also knocked shares in the travel and airline sectors, with shares in Europe's largest travel operator TUI falling nearly 5% on the day and Lufthansa down 4.4%.

"At the outbreak of the Ukraine conflict and the Israel-Gaza conflict last year there was a weakening of demand for travel across the board in Europe, which eased after a couple of weeks," said Andrew Lobbenberg, an analyst at Barclays.

Iran launched its largest missile attack against Israel on Tuesday in retaliation for Israel's campaign against Iran-backed Hezbollah in Lebanon, prompting a threat from Israel of a "painful response".

On Wednesday afternoon, flights were seen over Iranian airspace, according to a FlightRadar24 map, including from carrier flydubai and Wizz Air, after Iran said its ballistic missile attack on Israel was over.

However, flights across the entire region were diverted or disrupted with little sign of broader normalisation, with some changing their routes to avoid certain airspace.

"All planes - mainly flights to India – are avoiding Iranian airspace until further notice," said a spokesperson for Polish flag carrier LOT.

Europe's aviation safety regulator EASA issued a conflict zone information bulletin on Wednesday advising airlines to avoid Iranian airspace "at all flight levels" as worries over retaliatory attacks from Israel targeting Iran rose.

It had earlier issued two similar bulletins at the end of September advising airlines not to use Israeli or Lebanese airspace.

Carriers around the world have cancelled flights to Israel and Lebanon in the wake of the escalating conflict, with many saying they won't resume until at least mid-October, depending on the security situation.

Both British Airways and Air France-KLM said their flight cancellations to Tel Aviv's Ben Gurion airport remained in place until at least early next week, including the Oct. 7 one-year anniversary of Hamas' attack on Israel.

Airport impact

Traffic over the Istanbul, Cairo and Antalya hubs remained dense as flights continued to avoid parts of Middle Eastern airspace.

All of the flights departing Abu Dhabi Zayed International Airport were delayed, while 56% of flights set to depart Ben Gurion airport in Tel Aviv were cancelled, according to the airline tracker.

At Amman's Queen Alia International Airport in Jordan, around 38% of arriving flights were cancelled.

The latest disruptions are expected to deal a further blow to an industry already facing a host of restrictions due to conflicts between Israel and Hamas, and Russia and Ukraine.