Which 1978 US television movie involves terrorists hijacking three commercial jets to drop atomic bombs on American cities?

In the four-hour 1978 telefilm “Evening in Byzantium”, Glenn Ford leads a cast of veteran US television performers. His character, Jesse Craig, is a film writer and producer whom many believe has retired. He attends the Cannes Film Festival to see a friend and show him a screenplay. It deals with terrorists hijacking commercial jets and using them to drop nuclear weapons on American cities. Ford’s character refuses to reveal the screenplay to anyone else and attributes it to an unknown writer.

Another American, residing and making films in Europe has brought along his own latest project is about third-world rebels. He has cast himself as their leader. He hears about the Ford character’s screenplay and arranges to get it secretly copied. He is terrified by what he reads, as he is an assassin who plans similar terrorism for Europe.

An associate of the assassin attempts to kill Craig but instead kills his love interest and injures Craig. In the hospital, Craig discovers what has been going on. Craig and his new love interest, a reporter, investigate. People die. The planes are hijacked, the passengers are held captive, and the jets are armed with atomic bombs. Craig kills the leader of the bad guys, gets the girl, and calls NATO, which notifies the US Air Force which, in turn, saves Washington, D.C., New York City, and Miami, Florida by shooting down the jets.