According to a report by the Center for Strategic and International Studies, the lack of funding caused by budget cutting became the main reason of shutting the programs down.
The Future Combat Systems for Army costing about $18.1 billion appeared to be the most expensive of all canceled projects. It was replaced by the Ground Combat Vehicle Program which was also eventually abandoned. The second spot in the chart is taken by Comanche helicopter project that cost some $7.9 billion.
Such pieces of equipment as XM2001 Crusader Self-Propelled Howitzer ($2.2 billion in losses), Armed Reconnaissance Helicopter ($500 miillion) and Aerial Common Sensor for shared use by Army and Navy ($100 million) as well as all Next Generation Bomber ($100 million) all made the cut.
The development of an Airborne Laser was named the most expensive Air Force project. Costing $5.2 billion, it was rejected without any replacement.
Moreover, the US declined the construction of the $1.9 billion E-10, a multi-sensor aircraft initially supposed to serve as a command center for conducting air fights and $200 million CSAR-X attack and rescue helicopter.
Among hardware planned for construction for the Marine Corps, the VH-71 Presidential Helicopter and Expeditionary Fighting Vehicle became the most unprofitable pieces. The US has spent $3.7 and $3.3 billion on those projects respectively.
US Navy projects that were either suspended or canceled include $200 million next generation cruiser CG(X) and $600 million Advanced SEAL Delivery System.