There seems to be conflicting reports about this with some saying the US is threatening those responsible for fueling the planes:
Iran Air says refueling stops may be necessary owing to fuel denial at Heathrow:
The statement comes as multiple media outlets report that a number of Western fuel providers are unwilling to conduct business with the carrier following sanctions imposed on the Iranian government earlier this year by the UN, US and EU. Ref. Source 6
Iran plans to buy 80-90 Boeing, Airbus planes a year, post sanctions:
"We will purchase planes from Boeing and Airbus in equal numbers," Khodakarami was quoted as saying, adding that Iran would initially need to add at least 80 planes to its fleet each year. That would mean a total of 300 planes within five years, he added. Ref. Source 8o
The recent deal between the Iranians and the US is obviously exciting them already to make a large purchase but do they really see big travel in their future? How many people want to go to Iran?