Russian Air Force chief Alexander Zelin paid an unscheduled visit to Cairo Tuesday. DEBKAfile: His arrival less than a week after Egypt’s strongman, Defense Minister Gen. Abdel-Fattah El-Sisi’s talks in Moscow, was hurriedly arranged to resolve differences over the types of Russian weapons to be included in Moscow’s arms transaction with Cairo. El-Sisi is holding out for top-of-line S-300 anti-missile batteries and long-range ballistic surface missiles.