On Tuesday and Wednesday, NATO jets scrambled to intercept at least 26 Russian military aircraft flying over Western Europe and the Black Sea. "These sizable Russian flights represent an unusual level of air activity over European airspace," NATO said, and since the fighter jets, bombers, and tankers typically don't file flight plans or use transponders, they put civilian aircraft at risk.This week's Cold War level of Russian aerial activity was unusual, but appears part of a pattern — NATO says it had had to conduct more than 100 intercepts in 2014, or about three times the number as all...