Russian Prime Minister Dmitry Medvedev has said the country is considering a ban on flights from Europe and the US to Asia.Speaking at a government meeting he said the "serious measure" of blocking Russian airspace was a response to sanctions that recently stopped Dobrolyot, one of Russia's low-cost airlines, from flying.
It comes as Mr Medvedev confirmed the country has banned transit flights for Ukrainian airlines via its territory.
If Russia goes ahead with the ban on Western airlines, passengers could see ticket prices rise because carriers would be forced to use more fuel to reach destinations using longer flight paths.
The move could hit major European airlines such as British Airways, Lufthansa and Air France, leaving them faced with multibillion-pound losses.
Meanwhile Russia announced further details on its sanctions on food and agricultural products from the West.
Mr Medvedev said an immediate ban has been put on fruit, vegetable, meat, fish, milk and dairy imports from the European Union, United States, Australia, Canada and Norway.
He said: "Until the last moment, we hoped that our foreign colleagues would understand that sanctions lead to a deadlock and no one needs them.
"But they didn't and the situation now requires us to take retaliatory measures."
He said the food ban would last for a year, but could be lifted earlier if the West reacted with a "constructive approach".
Responding to the decision, the European Commission warned it was ready "to take action".
In a statement it said: "This announcement is clearly politically motivated.
"Following full assessment by the Commission of the Russian Federation's measures, we reserve the right to take action as appropriate."
In 2013 the EU's agricultural exports to Russia were worth €11.8bn (£9.4bn), while the US says its food and agricultural exports amounted to $1.3bn (£77m).