The pilots of US Air Force F-35 fighters sent to intercept the mystery object over Alaska on Friday say that whatever it was had been “interfering with the sensors of their aircraft” before they shot it down. Three unidentified objects have been spotted over North America in the past 10 days. The first, a giant airship “the size of three buses” is understood to have originated in China although the US and Chinese governments disagree about its exact purpose. While the Pentagon says it was a spy balloon, China says the monster airship was a civilian craft designed to monitor...