International carriers have begun rerouting their flights away from the Tehran Flight Information Region (FIR) following an escalation in tensions between Iran and the United States.

On Thursday, June 20, Iran's Islamic Revolutionary Guard Corps (IRGC) shot down a US Northrop RQ-4A Global Hawk BAMS-D surveillance drone that it claimed had violated Iranian airspace. It added that it could have also downed a surveillance-gathering Boeing P-8 Poseidon that had been in the area at the time. US Central Command (CENTCOM) in turn rejected Tehran's claims adding that the drone had been in international airspace at the time of the incident.

On Friday, June 21, the US Federal Aviation Administration (FAA) issued an Emergency Order in which it banned all US civilian aircraft and operators from transiting the Tehran FIR in the area above the Persian Gulf and Gulf of Oman.

"All flight operations in the overwater area of the Tehran Flight Information Region (FIR) (OIIX) above the Persian Gulf and Gulf of Oman only are prohibited until further notice due to heightened military activities and increased political tensions in the region, which present an inadvertent risk to U.S. civil aviation operations and potential for miscalculation or misidentification," it said.

"The risk to U.S. civil aviation is demonstrated by the Iranian surface-to-air missile shoot-down of a U.S. unmanned aircraft system on 19 June 2019 while it was operating in the vicinity of civil air routes above the Gulf of Oman.

"There is also the potential for Iran to increase their use of Global Positioning System (GPS) jammers and other communication jamming capabilities, which may affect U.S. civil aviation operating in overwater airspace over the Persian Gulf and the Gulf of Oman."

Since then, the WAM news agency said Emirati carriers Emirates, Etihad Airways, flydubai, and Air Arabia have heeded a call by the UAE's General Civil Aviation Authority to "avoid operating in areas that could jeopardise civil aviation safety and operations". The bulk of their flights now transit Iraqi flight corridors with a handful of Etihad flights still using the Tehran FIR for North America-bound routes.

United Airlines has since suspended its New York Newark-Mumbai Int'l, India service until further notice while Lufthansa Group, Qantas, Air France, KLM Royal Dutch Airlines, Malaysia Airlines, and Singapore Airlines have all rerouted services that would have transited Iranian airspace. IndiGo Airlines and Air India have also stated they will adjust their respective flight paths accordingly.

For their part, Russian carriers and Qatar Airways continue to operate through Iranian airspace as usual.