In a move that will further develop South Korea's budding aerospace industry, the country's main airline plans to build Blackhawk helicopters under license from two U.S. companies, Sikorsky Aircraft and General Electric Co.

The contract with Korean Air calls for 80 to 100 helicopters to be produced as part of a program to modernize the South Korean armed forces. Sikorsky said its share of the job would be about $500 million. The South Korean Defense Ministry has valued the total program at $1 billion.

The deal calls for the first few of the 17-seat helicopters to be produced entirely in the United States. Later, Korean Air would expand its role to produce the bodies of the helicopters and parts of their engines. It would not handle the complex rotor systems, however, according to Sikorsky, a division of United Technologies Corp.

Paul Turk, director of publications at Avmark Inc., an aviation management consulting firm based in Rosslyn, said the deal would advance Korean capabilities in aerospace. He said it was unlikely that the country would try to produce large aircraft in the foreseeable future, saying it was focusing instead on small aircraft and components.

"I don't think you will see their own designs anytime soon," he said. "You will see licenses and co-production."

South Korea and McDonnell Douglas Corp. earlier this year signed a deal worth at least $3 billion for 120 F/A-18 fighter-bombers, most of them to be built in part in South Korea. That deal became the target of criticism from Capitol Hill, where some legislators said it constituted a short-sighted transfer of vital technology to a country that could emerge as an economic competitor.

Since the 1970s, South Korea has worked to build an aerospace industry. It has assembled Northrop F-5 fighter-bombers and Korean Air currently makes the fuselages for MD-500 helicopters that McDonnell Douglas sells worldwide. It has assembled about 300 complete MD-500s for the South Korean market.