A competition to provide Japan’s next generation of jet fighters is under way after U.S. and European aircraft makers submitted specifications and prices to Japan’s Defense Ministry on Monday.

Tokyo plans to buy about 40 new planes to serve as the country’s primary fighter jet. Analysts say the contract to replace Japan’s decades-old fleet of F-4 Phantoms could be worth several billion dollars and influence sales to other countries.

Two U.S. manufacturers are competing for the contract – Boeing with its FA-18 Super Hornet and Lockheed Martin with its F-35 Lightening Two, which was jointly developed by the U.S. and Britain.

European makers are offering the Eurofighter Typhoon, jointly developed by Britain, Germany, Italy and Spain.

The ministry plans to make a choice by the end of the year.

European firms believe that a sale to Japan, which has traditionally used U.S. fighters, could expand business worldwide.

U.S. manufacturers have benefited from a traditionally close defense relationship between the United States and Japan.