US Treasury Chief Says Iranian Airlines Could Be Effectively Shut Down Worldwide From September 23

US Treasury Secretary Scott Bessent has warned that Iranian airlines could be effectively shut out of international operations from September 23 as Washington intensifies sanctions pressure on Iran’s aviation sector.

Iranian airlines are facing potentially severe disruption to their international operations after the United States warned airports, fuel suppliers, ticketing companies and other service providers against continuing to support sanctioned Iranian carriers.

US Treasury Secretary Scott Bessent said on Monday, September 21, that he expects Iranian airlines to be effectively unable to operate internationally from Wednesday, September 23, as companies around the world face the threat of secondary US sanctions.

Speaking to CNBC, Bessent said that companies providing Iranian airlines with fuel, landing services or ticket sales could risk being excluded from parts of the US dollar-based financial system.

How Would the Restrictions Work?

The United States is not directly ordering every airport worldwide to close its doors to Iranian aircraft.

Instead, Washington is using economic sanctions to discourage foreign companies and airports from providing services that Iranian airlines need to operate internationally.

Those services can include:
•    Aircraft refuelling
•    Airport and landing services
•    Ground handling
•    Ticket sales
•    Cargo services
•    Financial transactions
•    Commercial representation and aviation support

Companies continuing certain dealings with designated Iranian airlines could expose themselves to US sanctions or restrictions on access to the American financial system.

This distinction is important: Bessent has described the expected result as a global shutdown, but whether every Iranian airline actually stops operating internationally from September 23 will depend in part on how foreign governments, airports and aviation-service companies respond to the US measures.

US Sanctioned 27 Iranian Airlines

The latest warning follows a major action by the US Treasury Department on September 8, 2026.

The Treasury’s Office of Foreign Assets Control, or OFAC, sanctioned 36 targets connected with Iran’s aviation industry, including 27 Iranian airlines.

The airlines designated in the September action include Iran Aseman Airlines, Iran Air Tour, Kish Airlines, Qeshm Air, Zagros Airlines, Sepehran Airlines and several other carriers.

The Treasury said the action was intended to target the remaining active Iranian airlines as part of Washington’s broader Operation Economic Outcast sanctions campaign.

Mahan Air had already been subject to US sanctions before the September measures.

Why Is Washington Targeting Iran’s Aviation Sector?

The US Treasury alleges that parts of Iran’s commercial aviation industry have been used to support military procurement and transport personnel, weapons and other cargo associated with the Islamic Revolutionary Guard Corps.

Washington has particularly accused Mahan Air of supporting the IRGC-Quds Force and assisting military-related activities.

Iran has previously rejected broader US efforts to economically isolate the country and has accused Washington of using sanctions to exert political and economic pressure.

The Treasury also says Iranian aviation companies have used intermediaries and front companies in third countries to acquire aircraft, components and technology subject to US restrictions.

International Flights Already Facing Pressure

Signs of the impact were visible even before the September 23 deadline.

Turkey and Oman had agreed to halt Mahan Air flights following discussions with the United States, while Mahan Air subsequently suspended services to destinations including Turkey.

These developments suggest Iranian carriers may face increasing difficulty securing airport services and maintaining international routes as companies assess their exposure to US sanctions.

Secondary Sanctions Put Foreign Companies Under Pressure

The effectiveness of the US strategy depends heavily on secondary sanctions.

Unlike restrictions that apply primarily to US companies or individuals, secondary sanctions can create consequences for foreign businesses that conduct certain transactions with sanctioned entities.

The US Treasury has warned that foreign financial institutions engaging in significant transactions involving designated entities can face restrictions on their ability to maintain accounts or conduct business through the United States.

Given the importance of the US dollar to international aviation, banking and fuel transactions, the threat could lead companies outside the United States to stop dealing with Iranian airlines even when their own governments have not formally prohibited those services.

What Happens on September 23?

September 23 should therefore be viewed as the date on which the US expects its sanctions pressure to significantly restrict Iranian airlines’ ability to operate internationally.

It does not necessarily mean that every Iranian domestic and international flight will automatically stop at the same moment worldwide.

The actual impact will depend on airline schedules, foreign government decisions and whether airports, fuel providers, financial institutions and other aviation companies continue providing services to Iranian carriers.

Passengers booked on Iranian airlines, particularly on international routes, should check directly with their carrier and destination airport for the latest operational information as the sanctions measures take effect.

The aviation restrictions are part of a wider US campaign aimed at increasing economic pressure on Tehran amid continued tensions between Washington and Iran.