Global airlines including British Airways, Qantas, KLM and Singapore Airlines are re-routing flights to avoid parts of Iran-controlled airspace, and all US carriers have been told to avoid the area.
Flight paths over the Strait of Hormuz and Gulf of Oman are being re-routed over concerns for the safety of commercial airlines after Iran used a surface-to-air missile to shoot down a US drone on Wednesday.
The incident prompted the US Federal Aviation Administration (FAA) to issue an emergency order temporarily banning carriers flying over the area.
The FAA said flight tracking devices showed the nearest civil aircraft was operating within around 45 nautical miles of the unmanned aircraft when it was shot down, according to Reuters.
"There were numerous civil aviation aircraft operating in the area at the time of the intercept," the FAA said.
It added: "The threat of a civil aircraft shootdown in southern Iran is real."
Malaysia Airlines, Qantas, Singapore Airlines and KLM are re-routing flights, with Singapore warning some journeys might require longer routings to avoid the area.
A British Airways spokeswoman said: "Our safety and security team are constantly liaising with authorities around the world as part of their comprehensive risk assessment into every route we operate." KLM said: "Safety is our top priority."
United Airlines suspended its flights to India through Iran airspace after a ‘thorough safety and security review’ yesterday.
A United spokesman said customers flying from Mumbai to Newark would be booked on alternative flights back to the United States, the Reuters report added.
