Last November the European Union said Russia had agreed to phase out over the next seven years over-flight charges for Asia-bound European airliners using Russian airspace.
Until now, European carriers have had to pay more than $300 million a year for flights over Siberia, the fastest route to destinations in China, Japan and Southeast Asia.
A long-standing dispute over over-flight fees, protested by the EU as a violation of the 1944 Chicago Convention on International Civil Aviation, has been a hurdle to Russia's bid to join the World Trade Organization.
Russia introduced the Trans-Siberian over-flight tax in 1969, when long-range jetliners came into widespread use. Until then, European carriers could take their Asia-bound passengers only as far as Moscow, and then hand them over to the Russian national carrier Aeroflot.
The mooted agreement is expected to be signed during the Russia-EU summit in May this year.