Those sanctions ban manufacturers from selling new aircraft or parts to Iranian companies, which has grounded much of the fleet.
Under an interim nuclear deal reached in November 2013, the sanctions were eased to allow the sale of parts and for making safety-related repairs.
The fleet consists of only 140 functioning aircraft, Ali Reza Jahangirian, head of the Iran Civil Aviation Organization (ICAO), was quoted Friday by state news agency IRNA as saying.
"That is lower than the average international norms in terms of international indexes of population and area," he said, adding that an eventual nuclear deal with world powers would ease the way toward solving the problem.
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"We will need 400 to 500 airplanes over the next 10 years," he said, without spelling out the types of aircraft involved or giving any indication of a possible budget.
Since the signature of the interim accord, Jahangirian said a number of airplane manufacturers have visited Iran to assess the market and to discuss possible agreements.
"Aircraft manufacturers are seriously working to forge interaction with Iran and not fall behind the race once the situation changes," he said.
The United States has allowed aircraft maker Boeing Co and leading engine manufacturer General Electric Co to sell parts.
Over the years, Iran has developed a domestic manufacturing capacity for airplanes to fly domestic routes, based on the Ukrainian Antonov 140 turboprop regional airliner.
It has also been able to buy or lease used aircraft, notably from Airbus Industries.