NATO aircraft have started policing Montenegro’s airspace, a year after the small state became a member of the Western military alliance. Italian and Greek warplanes conducted an exercise in the skies over the capital Podgorica on Tuesday. They intercepted an “intruder” aircraft and forced it to land in a symbolic start to the mission, AP reported. “From now on, our skies and the sea are protected,” Defense Minister Predrag Boskovic said. Montenegro joined NATO as the alliance’s 29th member despite opposition from Russia, which considers the Adriatic country a historic Slavic ally and is opposed to NATO’s enlargement. After separating from a union with Serbia in 2006, Montenegro was left without fixed-wing military aircraft and only has about a dozen operational helicopters.