Gulfstream builds the room before anyone decorates it, and the two things it sells are silence and air pressure.
Position
Founded in 1958 as a division of Grumman — Roy Grumman turned from wartime fighters to business aircraft built to the same standard — and now a General Dynamics subsidiary, Gulfstream has built close to two thousand aircraft. The G650 launched in 2008, first flew in 2009 and entered service in 2012; it cruises at Mach 0.85 with a ceiling of 51,000 feet, above most weather and most traffic.
Why it is in the Library
The G650 holds its cabin at about 3,000 feet of pressure altitude while flying at 41,000, and its cabin is quieter than most luxury cars. Those are hospitality specifications, not aviation ones. Nobody arrives from a fifteen-hour flight rested because of the seat; they arrive rested because the air was thicker and the noise was lower, and that is a decision taken by an airframe manufacturer years before any completion centre or designer is involved. The Library admits Gulfstream because the guest experience is largely settled at this stage.
What this model does not solve
Cabin altitude and quiet are bought with structural weight and cost, and both are invisible in the brochure photographs that sell the aircraft. The same airframes serve as government and military platforms — the C-37, the Compass Call, the CAEW — and the Library records that the civil and the military product are the same object.