The Boeing Pelican ULTRA is intended as a large-capacity transport craft initially for military use, with possible subsequent availability as a commercial freighter[1] serving the world's largest cargo centers.

[2] The design process for what became the Pelican began in early 2000, when designers in the Phantom Works division of Boeing started working on solutions for the United States Armed Forces objective of moving thousands of troops, weapons, military equipment, and provisions to a war or battle scene faster,[5] such as successfully deploying an Army brigade of 3,000 troops and 8,000 short tons (7,300 t) of equipment within ninety-six hours (4 days)[6] instead of the three to six months (91 to 183 days) it required in the past.

It applied for a patent in October 2001 on a ground effect airplane that would form the basis for the Pelican, aside from some eventually omitted design elements such as a T-tail, upward-pointing (positive dihedral) winglets, an additional middle row of landing gears, and a loading ramp at the back of the fuselage.

The next month, without explicitly naming Boeing as the aircraft originator, the Army cited the Pelican as an emerging technology to improve strategic responsiveness in its 2002 Transformation Roadmap.

[10] In July, a U.S. Transportation Command team lead at Scott Air Force Base mentioned the Pelican as a practical solution for moving troops and equipment over long distances.

As described in its physical form, the aircraft mostly resembled future versions of the Pelican, except that the winglets were reverted to upward-pointing to maximize lift.

[14] In the September 2002 edition of its company news magazine, Boeing published an article highlighting the Pelican and revealing more of its final specifications, including a 500-foot wingspan (152 m), a wing area of over one acre (43,560 sq ft; 4,047 m2), a payload of 1,400 short tons (1,270 t) of cargo, an increased flight service ceiling of 20,000 ft (6,100 m) or more in altitude, and a range for a smaller payload of 6,500 to 10,000 nautical miles (7,480 to 11,500 miles; 12,000 to 18,500 kilometres), depending on the flight mode.

[15] This article attracted international media coverage,[16] and as Boeing Phantom Works continued to mature the design (including selection of the mid-size vehicle option),[2] additional details about the aircraft began to appear over the next year in newspaper,[17][18][19][2] general science magazine,[20][21][6] and aviation industry print publications[22][23][1] and research conferences.

[25] According to Boeing, the Pelican aircraft technology was starting to gain followers among the decision makers evaluating the mobility initiatives within the Army and the Air Force,[26][10] and the Navy also showed interest though it was directing its attention more toward hybrid ultra-large airships (HULAs).

Taking some market share from ocean shipping could occur, contended Boeing, because in comparison with traditional air cargo transports, the Pelican is less expensive and offers much more payload volume and weight.

[33][29][4] At the 2004 Farnborough Air Show, Boeing announced that the Pelican had entered wind tunnel testing and that the aircraft's service ceiling was increased to 25,000 ft (7,600 m).

[14][1] Though Boeing filed a couple of patent applications in mid-2005 relating to cargo container handling[36] and automatic altitude measurement,[35] no other public announcements appear to have been made about the aircraft after the report was issued.

[37] Facing diminished odds of a large order from the U.S. armed forces, which collectively represented the aircraft's sole indispensable launch customer, Boeing quietly discontinued further development of the Pelican program.

[39] In its most efficient flight mode, the Pelican flies in ground effect at 20 to 50 feet (6.1 to 15.2 metres) above the water,[7] measured from the fixed structure (the underside of the fuselage), though the aircraft distance can be reduced to 10 to 40 ft (3.0 to 12.2 m) depending on its wingtip positioning.

It is capped in front by a large swing-nose door, which allows for loading and unloading cargo through both decks, and in back by conventional tailfin and tailplane stabilizers attached directly to the fuselage, instead of the heavier T-tail empennage that is typically used by other ground effect planes.

To let the aircraft change shape for different types of operations, the wings are hinged within the drooping sections, and the axis of rotation is parallel to the fuselage.

[12] Within a cumulative cargo area of 29,900 sq ft (2,780 m2; 0.69 acres; 0.278 ha),[21] the entire aircraft can transport 178 containers,[23] or the equivalent of a single-stacked, containerized freight train stretching over two-thirds of a mile (1.1 km) long.

The aircraft can alternatively carry that payload at high altitude with a decreased range of about 6,500 nmi (7,480 mi; 12,000 km),[22] or approximately the distance between New York City and Shanghai.

[47] However, according to the designer of the Aerocon Dash 1.6 wingship (a larger, sea-based ground effect vehicle that was investigated by DARPA a few years before the Pelican was proposed), regular Pelican operation at airports with high water tables underground may result in a type of seismic wave that leads to cracks in airport terminal buildings and eventually causes greater damage within months.

[50] For Pelican landings, a satisfactory airfield meets the desired runway length and width of 5,500 and 100 ft (1,676 and 30 m), respectively, and has a load classification number (LCN) of at least 30 if paved or 23 if unpaved.

[7] The aircraft's length and wingspan, however, make the Pelican too big for the "80-meter box," the informal name of the maximum size specified in the ICAO Aerodrome Reference Code.

A more ideal setup is to build dedicated ground infrastructure[7] at airports for transloading, such as cranes, railcars, and apron jacks, which approaches the sophistication of container terminal facilities used at the docks of major marine ports.