The Walter F. Hiltner Aviation and Space Collection consists of textual and visual materials from Dr. Walter F. Hiltner's time at the Boeing Company as an aerospace scientist. The materials primarily relate to lunar and space exploration research and programs, circa 1950s-1960s. The collection has been divided alphabetically into four series, Aircraft and missiles, Lunar exploration, Space exploration, and General. Within each series materials are organized alphabetically.

The first series, Aircraft and missiles, is relatively small and includes primarily textual items that touch upon the Boeing Bomarc missile, Military Air Transport Service (MATS), and general aviation. Materials include reports, articles, technical information, lecture notes, and Hiltner's patent for a liquid fuel reservoir for aircraft. Also present is a photographic reproduction of a concept for an unidentified aircraft, possibly a fixed wing or stealth design. There is also a 16x24-inch original painting by Jack Bird that depicts a United States Air Force MATS aircraft (tail number 10400) unloading or loading a military vehicle.

The second series, Lunar exploration, holds materials related to Boeing's early plans for lunar exploration programs and research. The highlight and strength in this series is the concept art, including reproductions of sketches and photographic reproductions of concept paintings related to a moon colony. Images depict lunar bases, buildings, vehicles, and individuals in spacesuits, often shown working. Several images pertain to Boeing's proposed environmental space laboratory and depict a potential site location, exterior building deisgn, and interior lab. Several images are identified as concept designs done by artist Fred Takasumi. Very few of the images include captions or contextual information but most include Boeing stamps or identification numbers.

The third series, Space exploration, is notable for its visual documentation of PARSECS, Boeing's Program for Astronomical Research and Scientific Experiments Concerning Space. It includes presentation panels and concept art which were part of pitch Hiltner gave in 1962 in Washington, D.C. to promote the program. PARSECS was divided into eight missions and Boeing's research objectives for space and planetary exploration were to satisfy the "space-system requirements" that would lead to "a logical evolutionary sequence of missions and vehicle concepts." Most of the concept designs in this series were done by artist Robert F. Fetterly. Images pertain to the various eight missions and depict a satellite observatory, moon colony, counter moon capsule, Martian explorer vehicle, a solar probe, a general purpose space capsule, and space vehicle Ecto Genesis, which resembles a balloon.

Also present in this series is a design report for a manned Mars mission and a 1957 New York Herald Tribune feature about International Geophysical Year. Two photographs and additional reproductions of concept designs for the Ranger program, which was a series of uncrewed missions designed to tke images of the lunar surface. The photographs depict the Ranger during a launch attempt and the concept designs depict the craft itself, its flight plan, and trajectory. Two photographs of Surveyor spacecraft, NASA's robotic spacecraft sent to the moon's surface, are also present. The images depict Surveyor in a room or laboratory. Additionally, four 20x30-inch cardboard-mounted photographs of stars are included.

The final series, General, is quite small containing just a few pieces of ephemera collected from various sources. Materials include a humourous diagram for a widget, materials related to the Boeing Spacearium ride at the 1962 World's Fair in Seattle, Washington, a concept proposal about desalinization of salt water, and an overview chronology of events that affected the United States space program.

Note that many of the photographic reproductions and concept art in the collection have faded and are discolored.