Airline Investment Act of 1993 - Amends the Federal Aviation Act of 1958 to redefine, for purposes of providing limited foreign ownership of a U.S. air carrier, the term "citizen of the United States" to include a corporation association in which at least 51 percent of the voting interest is owned or controlled by U.S. citizens and each non-U.S. citizen who owns or controls any voting interest implements an open skies agreement with the United States. Defines "open skies agreement with the United States" to mean an agreement between the United States and one or more countries whereby such country guarantees to the corporate and other U.S. citizens liberal access to air transportation routes and other air related services.