Aircrafts of Egyptian Air Force are seen flying over downtown Cairo during an air show displaying eight F-16 fighter jets delivered from the to Egypt in Cairo, Egypt, on July 31, 2015. (Xinhua/Ahmed Gomaa)

Aircrafts of Egyptian Air Force are seen flying over downtown Cairo during an air show displaying eight F-16 fighter jets delivered from the United States to Egypt in Cairo, Egypt, on July 31, 2015. (Xinhua/Ahmed Gomaa)

Aircrafts of Egyptian Air Force are seen flying over downtown Cairo during an air show displaying eight F-16 fighter jets delivered from the United States to Egypt in Cairo, Egypt, on July 31, 2015. (Xinhua/Ahmed Gomaa)

Aircrafts of Egyptian Air Force are seen flying over downtown Cairo during an air show displaying eight F-16 fighter jets delivered from the United States to Egypt in Cairo, Egypt, on July 31, 2015. (Xinhua/Ahmed Gomaa)

Aircrafts of Egyptian Air Force are seen flying over downtown Cairo during an air show displaying eight F-16 fighter jets delivered from the United States to Egypt in Cairo, Egypt, on July 31, 2015. (Xinhua/Ahmed Gomaa)