TUSTIN (AP) — The massive blimp-like aircraft flies but just barely, hovering only a dozen feet off a military hangar floor during flight testing south of Los Angeles. Still, the fact that the hulking 230-foot-long Aeroscraft could fly for just a few minutes represents a step forward in aviation, according to the engineers who developed it. The Department of Defense and NASA have invested $35 million in the prototype because of its potential to one day carry more cargo than any other aircraft to disaster zones and forward military bases.