By Jamie Freed and Tim Hepher (Reuters) -Ukraine closed its airspace to civilian flights on Thursday, citing a high risk to safety, while Europe’s aviation regulator also warned against the hazards to flying in bordering areas of Russia and Belarus, because of military activities. Russian President Vladimir Putin authorised a military operation in eastern Ukraine in what appeared to be the start of war in Europe. On its website, Ukraine State Air Traffic Services Enterprise said the country’s airspace was closed to civilian flights starting from 0045 GMT on Thursday, with air traffic services …