By Robert Wall 

DUBLIN -- Despite Iran's landmark purchases of new planes from Airbus SE and Boeing Co., some of the biggest aircraft-leasing companies remain leery about entering the country amid uncertainty over the incoming Trump administration's policy toward the Islamic Republic.

The country's flag carrier, Iran Air, last week received the first new jetliner from Airbus. The delivery came after Iran Air late last year finalized deals to buy 100 planes from the European plane maker and another 80 from Boeing. The orders are worth more than $34.5 billion at list price, though buyers typically get deep discounts.

But big aircraft lessors still are reluctant to do business in Iran. "We will remain cautious," said John Plueger, chief executive of Air Lease Corp.

The deals with the world's two largest jetliner makers are among the highest-profile deals between Iran and western companies since the completion of a nuclear pact between world powers, including the U.S., and Tehran. Many sanctions on Iran were eased in exchange for the country placing limits on its nuclear program.

Years of sanctions have left Iran with one of the world's oldest airline fleets in need of modernization. But full order books at Airbus and Boeing mean Iranian carriers can only slowly get new planes. Airbus is expected to hand over around nine planes this year, with the first jetliner from Boeing due next year, Iran Air's Chief Executive Farhad Parvaresh said last week.

Airlines looking for popular planes more quickly often turn to plane lessors to introduce such aircraft. In other cases lessors become the financiers of new aircraft ordered by airlines through so called sale-leaseback transactions.

President-elect Donald Trump, who is set to take office Friday, has voiced skepticism about the Iran accord and "we have to be mindful of that," Air Lease Corp.'s Mr. Plueger said Tuesday at an Airline Economics forum.

U.S. critics of the Iran deal have tried to block financing of the planes. Members of the House of Representatives this week introduced a bill to force the Trump administration's director of national intelligence to investigate whether planes operated by Iran Air or other carriers are being used to support terrorism.

"We're asking the intelligence community to provide a full accounting of Iran's use of commercial airlines to support its global network of terror proxies" including in Syria, Rep. Peter J. Roskam (R-IL) said in a statement Tuesday.

Businesses are worried the U.S. may reimpose sanctions. "There is a substantial snap-back risk," said Olaf Sachau, chief executive of Intrepid Aviation. Although he sees Iran as an attractive market for plane-leasing companies to do businesses, the U.S. election outcome means tapping the market isn't on the agenda for now.

Aengus Kelly, chief executive of AerCap Holdings NV, one of the world's largest plane lessors, Wednesday said the company would wait for greater clarity before considering business in Iran.

Any lease deal with Iran would need to be approved by the U.S. Department of the Treasury's Office of Foreign Assets Control rules, he said. "If you can make sure you are in compliance with all the sanctions, that is a market we will look at," he said at the annual Global Airfinance Conference.

Iran Air's Mr. Parvaresh has said he was hopeful the plane deals with Airbus and Boeing won't be voided. Airbus executives have expressed the expectation that even if Mr. Trump wouldn't have approved the export licenses, he wouldn't void them now that they have been granted.

Still, Mr. Plueger said he was looking for more visibility of what relations with Iran look like toward the end of the year before considering engaging with airlines there.

Write to Robert Wall at robert.wall@wsj.com

(END) Dow Jones Newswires

January 18, 2017 14:27 ET (19:27 GMT)