Sheila E. Widnall, associate provost and professor of aeronautics and astronautics at the Massachusetts Institute of Technology, becomes Secretary of the Air Force. Widnall is the first female Secretary for any of the armed services.
The U.S. began extensive air and artillery strikes against Islamic State group targets in Syria on Dec. 19 in retaliation for the killing of three Americans on Dec. 13 by a gunman affiliated with ISIS, U.S. officials said.
