Zion - In the second mid-air collision over the US in barely 24 hours, two small aircraft collided over a northern Illinois community yesterday, one slicing into the roof of a hospital and the other crumpling onto a residential street about six blocks away. Three people died. On Monday two single-engine private planes collided above suburban Los Angeles, killing all four people on board as they crashed near two major freeways choked with morning rush hour traffic.