Donald Trump has appointed Erika Kirk, the widow of murdered rightwing activist Charlie Kirk, to a key advisory board of the US Air Force Academy. The 37-year-old joins a number of other loyalists to the president on the 16-member panel of the academy's board of visitors, which according to its website "inquires into the morale, discipline, curriculum, instruction, physical equipment, fiscal affairs, academic methods and other matters" of the Colorado Springs military training facility.