Gulfstream Says Flight Testing of G300 and G400 Is Accelerating as More Aircraft Join Test Fleets

Gulfstream says flight-test efforts for its in-development super-midsize G300 and large-cabin G400 are accelerating, with more aircraft joining the parallel test campaigns. The company declined to forecast certification timelines for either program. Gulfstream's Burns said, "We don't have a prediction on when [the G400 will be certificated]... I don't make that call."

Assembly of the third G300 test aircraft is underway at licensee Israel Aerospace Industries in Tel Aviv, Israel. The first G300 flew in December and is provisionally due to begin initial deliveries in 2028. Burns said the aircraft continues to fly well and that the second G300 will fly very soon.

The G400, which is intended to complete Gulfstream's new-generation large-cabin family, first flew in August 2024 and was originally due for deliveries this year. Burns said the G400 is the fourth and final aircraft to join the test fleet. One of the initial G400 test aircraft also set a new city-pair speed record from Miami while on its way to be exhibited at NBAA.

As with other recent FAA and European Union Aviation Safety Agency (EASA) certification programs, the G400's timetable has lengthened because of more stringent regulatory requirements, particularly on software validation.

Gulfstream believes the G400 will benefit from lessons learned on the long-range G700 and G800. The G700 was launched in 2019 but was not certified until March 2024, roughly two years later than originally expected. The G800 first flew in 2022 and was certified 34 months later, in April 2025.

Burns said Gulfstream pressed regulators to modernize the certification process and use available tools more fully, which he said happened on the G800 more than ever before, and that he expects the G400 to benefit.

The G700 and G800 histories show how certification now shapes a new jet's market entry. The G700 reached certification about two years behind its original plan, and the G400's original delivery year has already passed with no replacement date given. Software validation, singled out as the main source of added regulatory scrutiny, now sits on the critical path of new-generation business jets, and manufacturers set delivery dates they cannot fully control.

For buyers holding positions in these programs, delivery dates therefore work as planning targets that move with regulatory progress. Gulfstream itself describes the 2028 G300 start of deliveries as provisional, and it will not put a date on G400 certification.

The next evidence will come from test-fleet progress: the second G300's first flight, which Burns says is coming very soon, and the completion of the third G300 under assembly in Tel Aviv. Whether the more complete use of certification tools seen on the G800 carries over to the G400 will show in how quickly that program moves once all four aircraft are flying.