The last flap of this magnitude was in 1973 during the Yom Kippur War. Isreal was very close to deploying nuclear weapons against Egypt, Syria, Iran, and Iraq.
My sense is that the UFO phenomenon (excluding sitings of UAVs etc) is based on a theory of Jaques Vallee. He believes that the UFO phenomenon is a kind of human self extinction fail safe mechanism.
I would not be surprised to see a tremendous increase in sightings the closer we get to a nuclear war. If TPTB beleive their is an external threat see Regans speech:
In 1988, President Ronald Reagan addressed the General Assembly of the United Nations. The speech has become known as his famous Disarmament speech.
In this address, he postulated upon his "fantasy" of an alien species, from outside this world, invading Earth. Reagan thought that such an event would unite the world and tear down national borders. He also said that an alien force is already amongst us.
As if this presidential statement to the world wasn't interesting enough, Check this out!
Reagan's speech writer, Rhett Dawson, for some unknown reason, tried to remove Reagan's "Extraterrestrial Threat" comments from his speech. The below image is the note from Reagan to Dawson instructing him to put his alien "Fantasy" back into the speech. (Source: The Reagan Presidential Library web site).
Remeber that Regan has always been the god of the conservatives.