Russia is considering imposing restrictions on European flights over the country to Asia in a reaction to the economic sanctions imposed by the European Union.According to Russian business publication Vedomosti, Russian officials at the Ministry of Transport and Ministry of Foreign Affairs are considering overflight restrictions or even total prohibition, although both ministries declined to comment.Flying around Russia will add significant costs for European carriers, with Vedomosti's source estimating an overflight ban could cost airlines such as IAG's British Airways, Lufthansa and Air France €1bn over three months. A decision has been made, a senior federal official was reported as saying, after proposals from various agencies. A person close to the Foreign Ministry was reported as saying that anti-EU measures, will be examined and "will not go unanswered".Shares in IAG were down 3.8% to 314.6p, Air France KLM was down 3.70% to €7.52, and Lufthansa was down 1.19% to €12.86.OH