China Eastern Airlines (600115.SS) said on Thursday it will buy another 100 C919 airplanes in a deal worth $10 billion at list prices, in what would be the largest ever order for the jet made by the Commercial Aircraft Corporation of China (COMAC).

The state-owned carrier said it had received a “substantial discount” for the deal and that the planes will be delivered in batches from 2024 to 2031. The list price for the C919 is $99 million but aircraft can be sold at discounts of up to 50%, especially for new models.

The deal comes five months after the Chinese passenger plane, developed by state-owned COMAC to rival Airbus SE’s (AIR.PA) A320neo and Boeing Co’s (BA.N) 737 MAX single-aisle jet families, took its first flight in May with China Eastern.

The Shanghai-headquartered, state-owned carrier is the first user of the C919 and has bought five of the jets, of which three have been delivered. The other two are expected to be delivered later this year.