As President Xi Jinping watched, two Chinese companies signed agreements in Brazil on Thursday to buy 60 jets from Brazilian aerospace conglomerate Embraer SA.

It is the largest order Embraer has ever got from China, and Chinese airline officials were optimistic about the deal's potential impact on the country's regional airline industry.

ICBC Financial Leasing Co made a confirmed order of 10 E-190 jetliners, and an identical "optional" order.

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HNA Group, the parent company of Hainan Airlines, China's fourth-largest carrier, will buy 40 E-190 jetliners worth about $2.1 billion based on the plane's list price, but the final price will be lower after discounts are factored in.

HNA Group's order includes 20 E190-E2s, which will be put into operation beginning in 2018. The first Chinese operator of E190-E2s will be Tianjin Airlines, a subsidiary of HNA Group and the country's largest regional carrier.

The order will be delivered beginning in July 2015.

HNA Group is optimistic about the regional market in China even though China's regional aviation industry is still in its early stages and doesn't yet measure up to global standards.

Statistics from the Civil Aviation Administration of China show that only 186 regional jets in China were operating at the end of 2013, and the country's entire fleet comprised 2,179 planes. By comparison, regional jets account for more than 20 percent of the entire global fleet.

"The regional aviation market in China is a huge, untapped market, as there are so many small and midsize cities," HNA Group Chairman Chen Feng said.

Many favorable factors, such as the development of western China, increasing tourism in China and the government's support of regional markets, will create growth in the next few years, Chen said.

The new orders will help Tianjin Airlines continue exploring the market with midsize passenger flow, said Liu Lu, Tianjin Airlines president.

Paulo Cesar Silva, president and CEO of commercial aviation at Embraer, said, "We are very honored to cooperate with Tianjin Airlines to develop in more new markets in China."

Embraer is the world's major regional aircraft builder and has over 50 percent of the market share of the global regional aviation market.

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