Commercial airlines around the world were contemplating on Monday how long to suspend Middle East flights as a conflict that has already cut off major flight routes entered a new phase following the attack by the United States on key Iranian nuclear sites, and Tehran vowed to defend itself.
The usually busy airspace stretching from Iran and Iraq to the Mediterranean has been largely empty of commercial air traffic for 10 days since Israel began strikes on Iran on June 13, as airlines divert, cancel and delay flights through the region due to airspace closures and safety concerns.
New cancellations of some flights by international carriers in recent days to usually resilient aviation hubs like Dubai, the world's busiest international airport, and Qatar's Doha, show how aviation industry concerns about the region have escalated.
However, some international airlines were resuming services on Monday.
Leading Asian carrier Singapore Airlines, which described the situation as "fluid," was set to resume flying to Dubai on Monday after canceling its Sunday flight from Singapore.
Similarly, Flightradar24 departure boards show British Airways, owned by IAG, was set to resume Dubai and Doha flights on Monday after canceling routes to and from those airports on Sunday.
Air France KLM canceled flights to and from Dubai and Riyadh on Sunday and Monday.
With Russian and Ukrainian airspace also closed to most airlines due to years of war, the Middle East has become a more important route for flights between Europe and Asia. Amid missile and airstrikes during the past 10 days, airlines have routed north via the Caspian Sea or south via Egypt and Saudi Arabia.
Added to increased fuel and crew costs from these long detours and cancellations, carriers also face a potential hike in jet fuel costs as oil prices rise following the U.S. attacks.
Proliferating conflict zones are an increasing operational burden on airlines, as aerial attacks raise worries about accidental or deliberate shoot-downs of commercial air traffic.
Location spoofing and GPS interference around political hot spots, where ground-based GPS systems broadcast incorrect positions that can send commercial airliners off course, are also growing issues for commercial aviation.
Flightradar24 told Reuters it had seen a "dramatic increase" in jamming and spoofing in recent days over the Persian Gulf. SkAI, a Swiss company that runs a GPS disruption map, late on Sunday said it had observed more than 150 aircraft spoofed in 24 hours there.
Safe Airspace, a website run by OPSGROUP, a membership-based organization that shares flight risk information, noted on Sunday that U.S. attacks on Iran's nuclear sites could heighten the threat to American operators in the region.
This could raise additional airspace risks in Gulf states like Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates, it said.
In the days before the U.S. strikes, American Airlines suspended flights to Qatar, and United Airlines and Air Canada did the same with flights to Dubai. They have yet to resume.
While international airlines are shying away from the region, local carriers in Jordan, Lebanon and Iraq are tentatively resuming some flights after widespread cancellations.
Israel is ramping up flights to help people return home and leave. The country's Airports Authority says that so-called rescue flights to the country would expand on Monday with 24 a day, although each flight would be limited to 50 passengers.
The authority said that, starting Monday, Israeli airlines will start to operate outbound flights from Israel.
Israeli airline El Al on Sunday said it had received about 25,000 applications to leave the country in about a day.
