Sovjets largest airbases before 1991 were built outside Russian border.
These bases were many and very large.
It is a problem today for Russia to build new bases. Many bases has to be withdrawn because they use very heavy aircraft such as MiG-25/MiG-31.
Today were is three bases who Russia considers in Byelorussia; Bobruisk, Baranovichi or Lida.
Russia have today very large problems with the economy and we maybee see what happens with the defence. A dollar is today worth three times the rubel.