The U.S. Army wanted a dedicated USAF presence on the battlefield to reduce fratricide, or the harm of friendly forces. This preference led to the creation of the air liaison officer (ALO) position. The ALO is an aeronautically rated officer that has spent a tour away from the cockpit, serving as the primary adviser to the ground commander on the capabilities and limitations of airpower. The Korean War revealed important flaws in the application of CAS. Firstly, the USAF preferred interdiction over fire support while the Army regarded support missions as the main concern for air forces. Then, the Army advocated a degree of decentralization for good reactivity, in contrast with the USAF-favored centralization of CAS. The third point dealt with the lack of training and joint culture, which are necessary for an adequate air-ground integration. Finally, USAF aircraft were not designed for CAS: "the advent of jet fighters, too fast to adjust their targets, and strategic bombers, too big to be used on theatre, rendered CAS much harder to implement".