A PLANE crashed at an air show Saturday in Racine, Wis., killing a pilot who had been flying erratically as part of a comedy act in which she pretended to be inexperienced. . . . ILSA KLINGHOFFER, the daughter of a Jewish-American murdered in the 1985 hijacking of the Italian cruise ship Achille Lauro, urged Italy Saturday to step up its efforts to capture the hijacking's fugitive mastermind. . . . FIVE MEN were shot dead in an apparent hit squad execution in a suburb of Rio de Janeiro, Brazil, Saturday by three gunmen who claimed to be policemen, officials said.
