This GAO report is about the Army's Aquila Remotely Piloted Vehicle (RPV), which has had numerous difficulties since it entered full-scale development in 1979. Among these have been technical performance problems and funding cuts, which have led to substantial cost growth and schedule slippage. During the past year, the emergence of critical performance problems during testing led to a major program restructuring and threatened the Aquila's future. Prior to these changes, costs to acquire the Aquila were estimated at about $2 billion. This estimate has not yet been revised to reflect the recent changes. Several RPV systems exist in addition to the Aquila. The Army considered these alternative systems in a study it made in 1984 from the standpoint of their possible availability and potential to perform in the stringent environment envisioned for Aquila's use. GAO found that although the study did not consider several factors which could have led to a more balanced comparison, the Army chose to continue the Aquila development because of its earlier availability. The Army's decision to continue Aquila's development was based primarily on its ability to perform the basic target acquisition and designation mission in a stringent environment, and on its availability for fielding earlier than alternative systems. Although the Army's 1984 study of the Aquila and the alternative systems concluded that the alternatives could be made to perform the mission in a demanding environment, they could not match Aquila's earlier availability.