C-38A Courier

Gulfstream G100
A G150 inflight, gear and flaps extended
Role	Business jet
Manufacturer	Gulfstream Aerospace
First flight	1994
Status	Active service, In production
Primary user	United States Air Force
Produced	1985-2017
Number built	265 : 145 Astra/G100 + 120 G150
Unit cost	US$15.7 million (2015)
Developed from	IAI Westwind
Variants	Gulfstream G200

The Gulfstream G100, formerly known as the IAI Astra SPX, is an Israel Aerospace Industries-manufactured twin-engine business jet, now produced for Gulfstream Aerospace. The United States Air Force designation for the G100 is C-38 Courier. Gulfstream announced the final sale of the G150 (a later derivative of the G100) in September 2016 and the last delivery by mid-2017.

Israel Aerospace Industries (IAI) developed the Astra from its Model 1124 Westwind business jet. Work on an improved Westwind began in the late 1970s, with the first prototype flight on March 19, 1984. The first production Astra flew on March 20, 1985, with FAA certification granted on August 29, 1985 and customer deliveries starting in 1986.

The original 1125 Astra was replaced by the Astra SP, announced in 1989; 37 were built. The third variant, the Astra SPX, flew for the first time in August 1994. This variant was renamed G100 from September 2002 following Gulfstream's acquisition of Galaxy Aerospace, which held the Astra certifications, in May 2001.

In September 2002, Gulfstream announced the improved G150, based on the G100. This latest variant features a wider and longer fuselage, updated avionics and an increase in maximum takeoff weight (MTOW) to 26,100 pounds (11,839 kg) compared to the G100's MTOW of 24,650 pounds (11,181 kg). It was certified by the FAA in late 2005. It has been certified for the steeper-than-normal approach path required to land at London City Airport. Production of the G100 was discontinued following certification of the G150. IAI continues to manufacture G150s in Israel and the completed airframes are then flown to the U.S. for interior outfitting. In September 2016, Gulfstream announced that, owing to slow sales, production would be stopped, with delivery of the final aircraft due in mid-2017.

The G100 was ordered for the United States Air Force (USAF) in 1997 as the C-38A Courier. The C-38A is in use by with the 201st Airlift Squadron at Andrews Air Force Base in Maryland. The C-38A replaced the earlier Learjet C-21. The C-38A differs from the standard Gulfstream G100, being fitted with various military avionics systems.