Speculation is swirling after a US Air Force plane often used for sensitive missions made a short stint in Moscow. The US Air Force C-37B was spotted flying to the Russian capital today (Feb. 14). Its unlikely flight path has made experts scratch their heads over the reason for the mysterious flight. The jet took off from Rotterdam, Netherlands, before flying over the Baltic Sea to Moscow, a Flightradar24 tracker shows. Trump sending America's secret information to Putin?