European allies have vowed to shoot down any Russian aircraft violating their airspace after Nato members accused Moscow of repeated incursions into the alliance’s territory in recent weeks. “If another missile or aircraft enters our space without permission, deliberately or by mistake, and gets shot down and the wreckage falls on Nato territory, please don’t come here to whine about it,” Poland’s foreign minister, Radosław Sikorski, told an emergency meeting of the UN security council in New York on Monday that was called to discuss a Russian airspace incursion over Estonia. His warning was echoed by Poland’s prime minister, Donald...