Boeing Co. has delivered the first 787-9 Dreamliner assembled at its North Charleston plant to United Airlines, the company said Tuesday. The jet is also the 250th Dreamliner Boeing has delivered.

The airplane was handed over Monday and flown to United’s hub in Denver, The Post and Courier reported. United is scheduled to receive the plant’s second 787-9 later this month, according to the newspaper.

The 787-9 is the second model in the Dreamliner family, with a fuselage 20 feet longer than the original 787-8. Boeing says it uses 20% less fuel, with 20% fewer emissions, than the airplanes it replaces.

Boeing South Carolina workers began building rear and mid-fuselage sections for the first 787-9 in early 2013 and shipped them to Everett, Wash., for final assembly, Boeing said. Final assembly of the first North Charleston 787-9 began in November 2014, and the airplane rolled out to the flight line in January and first flew in February.

Earlier this month, the Federal Aviation Administration added South Carolina-built 787-9s to Boeing’s production certificate after an audit of the site, allowing the plant to deliver the model, the company said. The plant’s 787-8s were added in July 2012.

“This is an incredible achievement for Boeing, and I’m proud to be a member of the Boeing South Carolina team,” said Beverly Wyse, vice president and general manager of Boeing South Carolina.

The jet is United’s fourth 787-9, joining 12 787-8s already in service, Boeing said. The other three 787-9s were built in Everett, The Post and Courier reported.

“Our customers have told us they love flying on the Dreamliner, and we’re excited to mark yet another first for the aircraft with this delivery from Boeing South Carolina,” said Ron Baur, United’s vice president of fleet.

Through February, Boeing had 1,072 orders for the Dreamliner, including 466 for the 787-9, the newspaper reported. It also had 139 orders for the longer 787-10, which will be built only in North Charleston starting in 2017.

The delivery came as the International Association of Machinists petitioned the National Labor Relations Board for a union election at Boeing’s North Charleston facilities. Boeing said Monday it had been notified of the petition and that it believes a union is not in the best interest of its South Carolina workers.