The Russian news agency TASS reports (source):
Two third of flying and technical personnel of the Russian air force received field practice during the military operation in Syria, Russian Defense Minister Sergei Shoigu said on Saturday on the air with the Rossiya 24 TV Channel.
“Speaking about aviation, I would say that a greater portion, two thirds of flying and technical staff, received in-field practice and had extensive combat practice. We now have many young pilots with one hundred and more tactical missions. We made scheduled rotations, so that as much flying staff as possible could participate in this operation, in the operation against international terrorism. However, this refers to other services as well,” the minister said.
Russia began its military operation in Syria on September 30, 2015. On December 11, 2017, Russian President Putin said, addressing Russian military servicemen at Hmeymim airbase, that the operation was over and ordered to reduce the number of Russian troops in that country.