International carriers faced significant flight disruptions on Monday following Iran's missile and drone attacks on Israel, which severely limited alternative options for planes navigating between Europe and Asia.
Iran's retaliatory strikes, involving more than 300 missiles and drones, most of which were intercepted by Israel's U.S.-backed missile defense system, created chaos in the aviation industry.
Over the past two days, at least a dozen airlines, including Australia's Qantas, Germany's Lufthansa, United Airlines and Air India, had to cancel or redirect flights.
This was the biggest single disruption to air travel since the terrorist attacks on the World Trade Center on Sept. 11, 2001, according to Mark Zee, founder of OPSGROUP, which monitors airspace and airports.
"Not since then have we had a situation with that many different air spaces closed down in that quick succession and that creates chaos," Zee told Reuters, adding that disruptions were likely to last a couple more days.
The attack was in response to a suspected Israeli airstrike on Iran's Syria Consulate on April 1, in which seven Iranian Revolutionary Guards commanders and officers were killed.
The latest routing problems are a blow to an industry already facing a host of restrictions due to Israel's attacks on Gaza and the Russia-Ukraine war.
Airlines using Iran's airspace for travel between Europe and Asia will be restricted to two viable alternative routes, either through Türkiye or via Egypt and Saudi Arabia, according to Zee.
Israel initially closed its airspace on Saturday but reopened it on Sunday morning. Jordan, Iraq and Lebanon also resumed flights over their territories.
Major Middle Eastern airlines, including Emirates Airlines, Qatar Airways and Etihad Airways, said on Sunday they would resume operations in the region after canceling or rerouting some flights.
Europe's aviation regulator reaffirmed advice to airlines on Monday to use caution in Israeli and Iranian airspace. However, it said no civil overflights had been placed at risk during weekend tensions.
The European Union Aviation Safety Agency (EASA) and the European Commission said it would "continue to closely monitor the situation to assess any potential safety risks for EU aircraft operators and be ready to act as appropriate."
EASA guidance that is already in place for airlines in Israel and Iran continues to apply, the agency said in an emailed note.
That included exercising caution and following all available aeronautical publications for Israel and neighboring airspace up to 100 nautical miles surrounding the country.
For Iran, caution was recommended and said, "There continues to be an increased potential for miscalculation and misidentification" in the airspace over the Iranian capital, Tehran.
Disruptions continue
Meanwhile, some routes continue to be affected.
Germany's Lufthansa suspended regular flights to and from Tel Aviv, Irbil and Amman until Monday. Flights to Beirut and Tehran will remain suspended until at least Thursday.
KLM canceled all flights to and from Tel Aviv until Tuesday, a spokesperson for the Dutch arm of Air France KLM said on Monday.
Britain's easyJet paused operations to and from Tel Aviv on Sunday without providing a timeframe.
Wizz Air said it had canceled most of its flights to and from Tel Aviv on Saturday through Monday.
Finnair suspended operations in Iranian airspace until further notice, which may cause longer flight times on flights from Doha. A spokesperson said the Finnish carrier will reroute over Egypt, resulting in delays of a "few minutes."
A SAS spokesperson said flights between Copenhagen and Bangkok fly partially over the region and one flight had to reroute on the night between Saturday and Sunday.
IAG-owned Iberia Express said on X it would cancel flights to Tel Aviv on Sunday and Monday.
United Airlines canceled Sunday's planned flight from Newark to Tel Aviv, it said in an emailed statement to Reuters.
Air Canada warned of long delays and cancellations on its Israel flights and canceled flights to Tel Aviv on Monday and Tuesday.
Australia's Qantas Airways said on Saturday it had temporarily rerouted flights between Perth and London.
China Southern Airlines canceled Sunday's flight to Iran and Hainan Airlines said it is monitoring the situation and evaluating whether an upcoming flight to Israel can fly normally, Chinese business outlet Yicai reported.
Air India has canceled its flights to and from Tel Aviv until April 20. According to flight tracking platform Flightradar 24, the airline ran five weekly flights to the Israeli city.
Israel's El Al Airlines canceled 15 flights scheduled for Saturday and Sunday.
Smaller Israeli carrier Arkia said it was adjusting its flight schedule after initially postponing flights to Athens, Milan and Geneva.
According to a statement from the Emirati airline on state news agency WAM, the closure of airspaces affected some Fly Dubai flights.
Indian carrier IndiGo has rerouted its daily flights to Istanbul from Delhi and Mumbai, according to Flightradar 24. The company did not issue a formal statement on the change. Both flights, which earlier flew over Iran, now fly through Central Asia.
Indian carrier Vistara, co-owned by Tata and Singapore Airlines, said it is "making changes to flight paths" of some of its flights without further details.
On the other hand, Etihad Airways canceled services to Tel Aviv, Israel and Amman on Sunday but said it planned to operate scheduled passenger and cargo services between Abu Dhabi and Tel Aviv, Amman and Beirut from Monday. It warned that "there may still be a risk of some knock-on disruption" through Monday.
Emirates Airlines resumed scheduled operations to and from Jordan, Lebanon and Iraq on Sunday afternoon, a spokesperson said.
Qatar Airways also resumed services to Amman, Beirut and Baghdad, it said in a post on X on Sunday.
It was not yet clear if the latest unrest would impact passenger demand, which has remained robust despite ongoing conflicts in Ukraine and Gaza, said Brendan Sobie, an independent aviation analyst.
"If the political situation and the conflicts continue to escalate, then at some point, people will be concerned about traveling, but so far that hasn't happened," Sobie said.