Iran will soon receive 24 factory-fresh Su-35 Flanker-E fighter jets that Russia initially built for Egypt, according to Western intelligence sources. Iranian pilots already reportedly received training in Russia over the spring. But which Iranian pilots will ultimately fly them – those serving in the regular air force, the Islamic Republic of Iran Air Force (IRIAF), or those serving in the IRGC-AF, the air arm of the powerful Islamic Revolutionary Guard Corps paramilitary? 

Whoever ends up flying them could prove significant. Since taking power in 1979, the incumbent Islamist regime in Tehran has never trusted the regular army or air force. That's why it built up the IRGC as a loyal, parallel armed force that has long since outgunned the regular military. Iranian pilots who served in the pre-revolutionary air force were imprisoned, tortured, and even executed by the country's new rulers. The regime kept others alive only because it needed them to fight in the Iran-Iraq War (1980-88).

Aside from procuring Chengdu F-7 fighters from China during the 1980s, post-1979 Iran only made one significant fighter procurement, in 1990 when it bought MiG-29 Fulcrum fighter jets and Su-24 Fencer bombers for the IRIAF from the Soviet Union. 

Since then, it has not ordered any new planes. In 2015, the IRIAF reportedly wanted at least 30 Su-30s to upgrade its aging fighter fleet but was overruled by the IRGC, whose priority at that time was helping keep Syria's embattled President Bashar al-Assad in power. 

But time has steadily taken its toll. Much of the IRIAF's fighter fleet still consists of American aircraft acquired in the 1960s and 1970s. A series of recent crashes resulting from accidents and technical issues demonstrate that this fleet cannot remain airworthy forever, never mind keeping adequately up-to-date approximately half a century after entering service. 

Tehran's decision to seize a rare opportunity to acquire brand-new fighters could be an acknowledgment of this reality rather than a sign that it trusts the IRIAF more or has plans to supply the IRGC-AF with these jets. 

"They'll most likely serve in the national air force (IRIAF)," Farzin Nadimi, a defense and security analyst and Associate Fellow of the Washington Institute for Near East Policy, told me. "They'll most likely be of a specially trusted cadre of the air force, like those of the Su-24 72nd Squadron." 

Nadimi doesn't see the procurement for the IRIAF as a sign that the IRGC or the regime has any more trust in the regular air force. "It's mainly because the IRGC can't handle modern fighter jets and lacks the infrastructure and organization," he said. "Despite having a small fleet of Su-22 attack aircraft, the IRGC's air force is mainly built around ballistic missiles."