The Wall Street Journal confirms its report that U.S. investigators suspect Malaysia Airlines Flight 370 stayed in the air for up to four hours past the time it reached its last confirmed location. The Journal has since learned, however, that this belief is based on an analysis of signals sent through the Boeing 777s satellite-communication link, and not from data sent by the planes Rolls-Royce engines to Rolls Royce, as was earlier incorrectly reported. Our report has been corrected.