(Reuters) - Delta Air Lines fueled the appetite of planemakers on Tuesday after Chief Executive Ed Bastian said the airline planned to replace some 200 Boeing 757 and 767 aircraft over the next decade.

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The plans come as the second largest U.S. airline seeks to grow internationally, though Bastian said at a conference that the company had not yet decided whether to invest in struggling Italian carrier Alitalia.

Atlanta-based Delta’s potential fleet order, which analysts say would be worth over $10 billion, could boost proposals by Boeing Co to launch a new plane in that segment while Airbus is preparing to counter with a new version of A321 and the larger A330neo.

Delta is “very interested” and in discussions with Boeing about its proposed new midsized airplane, known as the NMA, Bastian said. Boeing will decide in 2020 whether to produce the plane which industry sources say would have two aisles and seat seven across.

The plane aims to address the so-called middle of the jet market between traditional narrowbody jets with one aisle and long-distance widebody planes.

“Hopefully they’ll decide to go,” Bastian said.

Delta is already in the process of replacing one-third of its mainline fleet, one of the largest and oldest among U.S. airlines, in the next five years.

Delta shares were up 2.5 percent at $50.03 in afternoon trading after Bastian said spring and summer travel demand was solid.

ALITALIA INVESTMENT?

Bastian said it was too early to decide whether to invest in Alitalia, which was put under special administration in 2017 after workers rejected the latest in a long line of rescue plans, leaving the Italian government seeking a buyer to save the airline.

Italy’s state-controlled railway Ferrovie dello Stato (FS) said last month it would start negotiations with Delta and EasyJet Plc to draft a rescue plan, the third in a decade, for the struggling airline.

Delta executives have held talks in Rome in recent weeks, according to Italian industry sources, but doubts remain whether an outside investor would be willing to take a minority stake in the strike-prone airline.

Bastian said that the numbers being thrown around for Alitalia are “pretty large” and “not the kind of numbers that we’re considering, just to quell any concerns.”

Still, he said it makes sense to consider an investment in Italy, an important market for U.S. consumers, and noted that Delta’s global growth over time will skew toward international rather than congested domestic markets.

That growth could come through direct investments in overseas carriers.

“You can’t actually own partner carriers so you have to find ways to influence them beyond just a commercial contract as a partner, and what we have found is that by making an investment into these businesses we can get actually inside the board room and help to start shape the strategy.”