Back in 1972, president Nixon wanted Sky Marshalls on all flights in the US and almost everyone especially secy. of State Kissinger opposed the idea. Even after threats from the PLO snd a particular highjacking in the US at the time in which the highjackers said that if they did not recieve the money that they were going to fly the jet into a Nuclear reactor. The president was very concerned about terrorism at the time but experts in the state department, the CIA and NSC thought not. On September eleventh, 2001, flight 175 out of Boston was highjacked and flew right over Indian Point which has two operating reactors. The plane was deliberately crashed into the World Trade Center but who knows how much worse the disaster could have been had it crashed into the reactor instead.