The secondary sanctions imposed by the United States on Iran are rapidly translating into real pressure. After the September 23 deadline, several Gulf neighbors, including the UAE and Oman, suspended flights from Iranian airlines, marking the first significant practical impact of Washington extending its sanctions to companies in third countries. Simultaneously, Saudi Arabia announced the interception of six ballistic missiles launched by the Houthi rebels in Yemen, further escalating the conflict into a new front in the Middle East. These overlapping developments are accelerating Iran's dual isolation in both the aviation and economic spheres.

I. A pre-announced "air blockade"

The September 23 deadline set by the U.S. Treasury Department has passed. From that day forward, any foreign company providing fuel, ground handling, or ticket sales to Iranian airlines will be excluded from the dollar financial system. U.S. Treasury Secretary Scott Bessant stated bluntly in an interview: “All Iranian airlines will be grounded globally. If any airport, fuel supplier, ground handling company, or ticketing agency continues to provide services to Iranian airlines, it will lose its eligibility for access to the dollar financial system due to U.S. secondary sanctions.” The U.S. Treasury Department had previously added nearly 30 Iranian airlines to its sanctions list, including agents of Mahan Air, Iran’s largest private airline, and 27 smaller airlines. The reason given by the U.S. is that Iran uses civilian flights to transport weapons and combat personnel, and Mahan Air is alleged to have ties to the Iranian Islamic Revolutionary Guard Corps. This sanctions strategy has been dubbed “Economic Day” by Trump himself, who compared it to the Allied invasion of Nazi-controlled France during World War II. However, unlike military action, the weapon in this “battle” is the dollar clearing system, and the target is every company worldwide that does business with the Iranian aviation industry.

II. Gulf neighbors take the lead: UAE and Oman close their airspace.

Less than 24 hours after the sanctions took effect, Iran's neighbors began to act. On September 24, the UAE General Authority of Civil Aviation issued a statement announcing the suspension of all flights to and from the UAE operated by Iranian airlines, effective immediately until further notice. The statement explicitly stated that this decision was "based on the US sanctions imposed on Iranian airlines." The UAE is the largest aviation hub in the Middle East, and Dubai International Airport has long been a crucial transit point for Iranian passengers and cargo traveling to and from the world. The severing of this route directly impacts Iran's international connectivity. Oman did not hesitate either. According to Iran's Tasnim News Agency, flights to Oman, Georgia, Azerbaijan, and Baghdad, the capital of Iraq, have all been suspended. The Iranian Civil Aviation Organization announced that flights from Tehran to Baghdad and Muscat were canceled from midnight on September 23, and authorities are attempting to divert some flights to Najaf, the Shiite holy city in Iraq. Georgia had already taken the lead, announcing on September 22 that it would cease receiving flights from Iranian airlines. In Turkey, Mahan Air has also suspended flights from Tehran to Istanbul and Ankara. A flight schedule released Thursday by Tehran's Imam Khomeini Airport shows that flights to and from Afghanistan, China, Iraq, and Turkey are still operating, but flights to and from neighboring Gulf countries have disappeared from the schedule. For Iran, which has long relied on the Gulf states as gateways for business and travel, this "selective suspension of flights" means that its air network is being gradually reduced to at least a few destinations that are still willing to withstand US pressure.

III. Iran's Response and the Daily Life of the "Open-Air Prison"

Iran has not stood idly by. A senior Iranian official threatened that if regional countries comply with US sanctions, Iran will ensure their airports become "unusable." This is not empty intimidation—Iran possesses a large number of ballistic missiles and drones and has repeatedly demonstrated its ability to strike regional targets. However, the threat cannot change the fact that Iran's aviation network is visibly shrinking. A retired Tehran teacher said, "We're like living in an open-air prison." This captures the real cost of sanctions—it doesn't fall on the abstract "aviation industry," but on every ordinary person who needs to travel abroad for medical treatment, visiting relatives, or doing business. Iranian airlines have long been responsible for transporting critical supplies such as medicine and auto parts, and are also the core channel for Iranians to travel abroad. Matthew Levitt, a senior fellow at the Washington-based Near East Policy Institute, told the Wall Street Journal that if the world truly cooperates with the sanctions, "Iranian airlines will be reduced to airlines operating only domestic routes." The Iranian economy is already under immense pressure. The local currency, the rial, fell to a historic low in August, breaking the 2 million to 1 exchange rate against the dollar, and the domestic inflation rate reached 66%. Iranian President Peshichiyan previously admitted that the comprehensive US sanctions and maritime blockade have caused the country's foreign trade to plummet by about 35%. With sea lanes blocked and air routes now closing, Iran is transforming from a "sanctioned country" into a "besieged country."

IV. Simultaneous Escalation of the Battlefield in Yemen: Missiles, Displacement, and the Red Sea Crisis

While Gulf states are busy closing their airspace, the conflict in Yemen is escalating geopolitical pressures on Iran in another direction. On September 24, the Saudi-led coalition announced it had intercepted and destroyed six ballistic missiles launched by the Houthis, targeting the Saudi cities of Taif and Yanbu. The Houthis claimed responsibility for attacks that day on a "sensitive target" in Riyadh, Saudi Aramco facilities in Yanbu, and multiple military targets in the Jizan region, using ballistic missiles, cruise missiles, and drones. Since announcing a blockade of Saudi Arabia in July, the Houthis have launched an offensive against the Saudi-backed Yemeni government this month, while the Saudi Air Force has carried out hundreds of airstrikes on Yemen. After seizing control of Yemen's entire Red Sea coast, the Houthis are advancing towards Taiz and the road leading to Aden. The Houthis claim that since the escalation of the conflict, Saudi Arabia has launched 1,018 attacks on Houthi-controlled areas. The humanitarian cost is rising sharply. According to UN data, the current escalation of the conflict in Yemen has resulted in nearly 700 deaths, thousands of injuries, and more than 125,000 people internally displaced. Thousands more have risked crossing the Bab el-Mandeb Strait by boat to reach Djibouti and Somalia in Africa. Almen Yadgalian, the UNHCR representative in Yemen, stated that more than 125,000 people have been forced to flee their homes in just one or two weeks, the majority of whom are women, children, and the elderly.

V. The Boundaries of Sanctions: Who is Enforcing Them, and Who is Watching?

The core logic of this "economic showdown" is that the US not only wants to stop doing business with Iran itself, but also wants to determine whether other countries in the world can do business with Iran. However, this logic is facing a real-world test. Chinese Foreign Ministry spokesperson Guo Jiakun clearly stated that China "has consistently opposed illegal unilateral sanctions lacking a basis in international law and not authorized by the UN Security Council." Russia has also refused to cooperate with the sanctions. It is noteworthy that this disagreement adds a diplomatic variable to Washington's sanctions implementation as the leaders of China and the US are about to hold a summit. However, for most countries and businesses, the allure of dollar clearing channels far outweighs the benefits of doing business with Iran. The UAE's choice is indicative—this Gulf state with deep commercial ties to Iran ultimately chose to comply with US sanctions. When a hub like Dubai, with decades of trade relations with Iran, chooses to close, the prospect of Iran's aviation industry becoming "domestic" is no longer just an analyst's hypothesis.

Editor's Summary

The US expansion of its sanctions tool from targeting Iranian entities to third-country service providers marks a qualitative shift in its strategy of economic pressure on Iran. Unlike traditional asset freezes or trade bans, secondary sanctions operate by forcing global companies to choose between the US market and their Iranian operations. The speed of this strategy's implementation in the aviation sector was unexpected—the UAE and Oman closed their airspace just one day after the sanctions took effect, cutting off Iran's most important external air corridor. However, the effects of the sanctions have clear limits. China and Russia refused to cooperate, and some of Mahan Air's Asian routes continued to operate. The essence of the sanctions is not a "global grounding," but rather pushing Iran's aviation network from the core to the periphery of the global system—retaining a few destinations not bound by the dollar system while losing almost all short-haul connections within the region. Parallel to the aviation blockade is the escalation of the war in Yemen. Houthi attacks on Saudi oil facilities and large-scale Saudi airstrikes have created a new front in the conflict, and the displacement of over 125,000 Yemenis indicates that the cost of this war is being borne by the most vulnerable groups. Two fronts—economic sanctions and military conflict—are simultaneously exerting pressure within the same timeframe, creating multi-dimensional pressure on Iran and its regional allies. The next step in this situation will depend on Iran's tolerance threshold under the dual pressures of the air blockade and the war in Yemen, and whether key external powers such as China and Russia are willing to provide Iran with substantial economic buffers.

Frequently Asked Questions

Question 1: What are "secondary sanctions"? How do they differ from ordinary sanctions? Ordinary sanctions target the target country itself—for example, prohibiting US companies from trading with Iranian companies. Secondary sanctions extend the scope to companies and individuals in third countries: even if you are not a US company, as long as you have business dealings with Iranian airlines, the US can impose sanctions on you. The core method is to exclude you from the dollar financial system. This means you cannot conduct any international trade settlements involving dollars. This practice is controversial under international law because it effectively applies US domestic law to global companies. Question 2: Why would a Gulf state like the UAE cooperate with the US in sanctioning Iran? The UAE has deep commercial and geopolitical ties with Iran, and Dubai has long been an important transit point for Iran to circumvent sanctions for trade. However, the UAE is also a key US security partner in the Middle East, and its aviation, financial, and energy exports are highly dependent on the dollar system and the US market. With the US explicitly threatening to "kick out" non-compliant companies from the dollar system, the UAE faced a choice: retain its air routes to Iran or retain its right to access the world's largest financial system. The UAE's choice indicates that, under the current level of sanctions, the attractiveness of the dollar system outweighs the value of maintaining air links with Iran. Question 3: What does Iran's threat to render neighboring airports "unusable" signify? This is a signal of military escalation from Iran. Iran possesses a large number of short- and medium-range ballistic missiles and drones, and has previously launched multiple strikes against Saudi oil facilities and Israeli targets. If Iran acts on its threats, it means the regional conflict will escalate from a proxy war in Yemen to a direct Iranian military strike against the infrastructure of Gulf states. However, the effectiveness of this threat is questionable: Iran is already under pressure on multiple fronts, and opening a new front of direct military confrontation could lead to a further tightening of its economic blockade, or even trigger a larger-scale military response. Question 4: What impact do sanctions have on the lives of ordinary Iranians? The impact is direct and widespread. Iranian airlines are responsible for transporting imported medicines and auto parts; flight cancellations mean a further tightening of the supply chain for these goods. At the same time, the channels for ordinary Iranians to travel abroad for medical treatment, visiting relatives, or business trips have been significantly narrowed. The Iranian currency has fallen to a historic low, the inflation rate is as high as 66%, and foreign trade has plummeted by about 35%. The combined air blockade and existing maritime blockade have pushed Iran's economy further from "sanctioned" to "besieged," with the pressure of shortages and rising prices falling first on ordinary families. Question 5: What is the connection between the Yemeni conflict and the sanctions against Iran? The Houthi rebels are a key regional ally of Iran in Yemen, and their military operations are highly intertwined with Iran's strategic interests. While Iran itself suffers from air blockade and economic sanctions, the Houthi attacks on Saudi oil facilities and military targets constitute Iran's "proxy retaliation"—increasing the political cost to the United States by targeting its Gulf allies. The humanitarian cost of the Yemeni conflict—more than 700 deaths and over 125,000 displaced persons—is the most direct human consequence of this proxy conflict, and the security of Red Sea shipping faces a continued threat, with potential impacts on global energy trade that cannot be ignored.