 Walker published another professional article in 1933 , entitled " Bombardment Aviation : Bulwark of National Defense " . " Whenever we speak in terms of ' air force ' we are thinking of bombardment aviation , " he wrote , dismissing other forms of aviation . This was orthodox at the Air Corps Tactical School , which taught that " every dollar which goes into the building of auxiliary aviation and special types , which types are not essential for the efficient functioning of the striking force can only occur at the expense of that air force 's offensive power . " Walker 's major thesis was that " a determined air attack , once launched , is most difficult , if not impossible to stop when directed against land objectives . " At the conclusion of his article , he renewed his call for the creation of an independent air force " as a force with a distinct mission , of importance co @-@ equal to that of the Army and the Navy . " Walker 's persistent advocacy of strategic bombing led to frequent clashes with Captain Claire Chennault , who led instruction in pursuit aviation at the Air Corps Tactical School from 1931 to 1936 . Chennault believed that the right mix of fighters and ground defenses could successfully defeat a bomber assault and ridiculed Walker for suggesting that bombers could not be stopped , leading to " legendary " debates between the two . 
