Statistics are rather sketchy.
Total numbers of living WWII veterans in 2019: Russian Federation 75000, Ukraine 20000-30000, Belarus 10000. All other ex USSR countries probably not more 5000. These figures are very approximate and are based on several sources that I can find in Russian/Ukrainian sources. They include only those who fought for the USSR.
There were certainly veterans who emigrated: USA, Israel, Canada, Australia, etc.
Now a difficult part...
"Veteran" was not just a title in the USSR but also an instrument to obtain some perks, mostly in terms of social benefits. This trend survived in the 1990s and probably in the early 2000s until governments put their pensions and benefits systems in order. Since my childhood I knew people who were given veterans certificates despite they have been neither on the battlefield nor in reserve units. Let's assume that fake veterans make 20% of the total today (very modest estimate), therefore there are 96 000
real veterans in ex USSR territory.
According to this set of documents:
ВОЕННАЯ ЛИТЕРАТУРА --[ Военная история ]-- Советская авиация в Великой Отечественной войне 1941-1945 гг. в цифрах
there were 49 521 airmen in VVS RKKA (Army Air Force) in December 1944, on the frontline and in the reserve. I have no numbers for Navy air units, but let's assume 15% of the total (that was the average share of aircraft of the Navy). Let's round up to 58 000 airmen total at the end of the war.
RKKA (Red Army) in January 1945 - 11 365 000 (Wiki)
Soviet Navy - probably 300 000 (my estimate)
Air force personnel other than airmen... - 100 000? (just my wild guess)
(I omit NKVD forces as their units were transferred in and out of Red Army all the time)
Then, airmen share in 1944-1945 was 0.5% of all servicemen of all military branches.
Assuming that mortality rates were equal for all since 1945, we come to this figure of living Soviet aviators - veterans of WWII:
0.5% of 96 000 = 480.
A lot of guesswork, of course.