What would happen if an airplane flew into a tornado?
It’s an exceedingly dangerous scenario — easily the worst possible wind shear situation imaginable in a thunderstorm. While tests have been conducted exposing aircraft to virtually all other meteorological hazards, any conclusion on the outcome of a tornado encounter is pure conjecture. The results in the air would be no better than an aircraft exposed to a tornado on an airstrip.
The National Transportation Safety Board tells us no explicit record exists of an aircraft/tornado encounter. At least a close encounter with a tornado in the potentially tornadic southwest quadrant of a thunderstorm involved the crash of a Southern Airways DC-9 near Hope, Georgia, on April 4, 1977.