Three aging Air Force veterans came to Washington, D.C., on Tuesday to again tell their strange and extraordinary stories. A fourth veteran was piped into the National Press Club conference by video feed from the Ozark Mountains in Missouri. Each veteran's story is different, but all share one central claim: In the 1960s, UFOs tampered with nuclear weapons managed by the Air Force, both terrifying and mystifying the airmen who experienced the encounters. Some remained silent for decades, they say. And none has captured the attention of Washington, even as reports of Navy encounters with unknown flying objects have splashed...