IIRC, a Niven story about some guy who pretends he's suicidal to deal with an attempted hijacking by a hitchhiker.

Actually, they've already talked about neg-G maneuvers, partial depressurization of the cabin, etc. in other forums - at least, one of the books you guys recommended (How Did This Happen?) pointed that out. Suggested that those procedures combined with air marshalls + secure cockpit seemed more likely to achieve the desired aims than the current "give the pilots guns" argument that everybody keeps having.