On Tuesday, the Alliance's fighters intercepted an IL-76 transport plane flying from Kaliningrad to mainland Russia.
The jets took off three times on Thursday to intercept an AN-26 transport plane flying from mainland Russia to its Baltic Sea exclave, another AN-26 flying in the opposite direction, and an AN-148 passenger aircraft flying to Kaliningrad.
A third An-26 plane was intercepted on its way from the exclave to mainland Russia exclave on Friday.
All of the Russian aircraft maintained radio communication with the regional air traffic control center, but some of them had their onboard transponders off and had failed to file their flight plans.
The NATO air-policing mission is conducted from Lithuania and Estonia.