U.S. Democratic presidential candidate Hillary Clinton waves as she boards her campaign plane in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria

Republican presidential nominee Donald Trump delivers remarks at a campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

U.S. Democratic presidential candidate Hillary Clinton speaks at the Black Women's Agenda Annual Symposium in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria

U.S. Democratic presidential candidate Hillary Clinton leaves after speaking at the Black Women's Agenda Annual Symposium in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria

Model plane builder Otto Dieffenbach III makes his remote control plane resembling Donald Trump release fake money as it flies over the beach next to a similar plane resembling Hillary Clinton in Carlsbad, California. REUTERS/Mike Blake

11-Year-old Millie March wears socks with the image of Republican presidential nominee Donald Trump on them at a Trump campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar

U.S. Democratic presidential candidate Hillary Clinton leaves after speaking at the Black Women's Agenda Annual Symposium in Washington, U.S., September 16, 2016. REUTERS/Carlos Barria

Republican presidential nominee Donald Trump delivers remarks at a campaign event at the Trump International Hotel in Washington, D.C., U.S., September 16, 2016. REUTERS/Mike Segar