A IranAir Boeing 747SP aircraft is pictured before leaving Tehran's Mehrabad airport Sept. 19, 2011. Reuters

Iran's transport authority announced Sunday it had paid half-price for a $16.6 billion deal to buy 80 U.S.-made Boeing airplanes in the nation's biggest Western contract since its 1979 Islamic Revolution.

The nation has faced significant difficulties replacing its aging passenger aircraft under global economic restrictions that punished international firms from doing business with Iran until President Barack Obama gathered other major world leaders and reached the Joint Comprehensive Plan of Action in 2015. Under the deal, billions of dollars worth of Tehran's assets were unfrozen in exchange for limiting its nuclear program.

The Boeing deal reached earlier this month signaled renewed interest of foreign business in Iran. "Boeing has announced that its IranAir contract is worth $16.6 billion. However, considering the nature of our order and its choice possibilities, the purchase contract for 80 Boeing aircraft is worth about 50 percent of that amount," Deputy Transport Minister Asghar Fakhrieh-Kashan told Iran's state-run IRNA news outlet.

IranAir, the nation's flag carrier airline, secured a contract Thursday with France's Airbus for 100 aircrafts, worth between $18 and $20 billion. IranAir's head Farhad Pavaresh said it had negotiated the price down to no more than $10 billion, partly because it dropped an order of superjumbo A380s. Kashan said Sunday Iran was also planning on purchasing more aircraft from French-Italian ATR, doubling the already 20 airplanes agreed on. Representatives from ATR were set to visit Tehran Wednesday to finalize talks.

"The purchase of 20 planes has been finalized and Iran may buy 20 more planes," said Fakhrieh-Kashan, later adding that the original contract was worth less than $500 million.

Despite the antiquated state of affairs currently plaguing Iran's commercial air fleet, the country saw 440,000 international flights last week with 6 million international travelers, Civil Chairman of the Parliament Mohammed Reda Rezae Kochi told IRNA Monday. He said the aviation industry expected significant increases in capacity and revenue following the massive purchases this year.