A ban on direct services between Ukraine and Russia has come into effect.
The suspension of flights is part of sanctions imposed on Russia for its support of separatists in the east.
Travelers between the two nations will now have to fly through another country, take the overnight train or drive.
It is predicted around 70,000 passengers a month will be hit by the ban.
The sanctions are intended to punish Russia for annexing Crimea and supporting armed rebels in eastern Ukraine despite a ceasefire on the ground.
According to Reuters around 8,000 people have been killed since fighting started in eastern Ukraine in April 2014.
The EU and the US have imposed their own sanctions against Russia over the conflict.