The past participle and past-tense form of the verb fly is usually flew. The only exception comes in baseball and softball, where a fly out (two words) is an out recorded when a batted ball is caught in the outfield. For example, if a batter hits a ball that gets caught by the right fielder deep in the outfield, later we would say the batter flied out to right.
This might sound incorrect to anyone who doesn’t follow baseball, but the argument over whether flied is correct was settled long ago. In baseball, there is no controversy over the issue. In fact, many baseball fans would hear flew out in this context as incorrect.
Trailing the Cleveland Indians by two runs in the ninth inning, Derrek Lee flied out on closer Chris Perez’s first pitch. [Washington Post]
Daniel Descalso sacrificed Molina to third, but pinch-hitter John Jay struck out and Theriot flied to right to end the inning. [Vancouver Sun]
After Miguel Tejada flied out to right, Kershaw walked his first batter of the game, rookie Brandon Belt. [Los Angeles Times]
Hanigan drew a walk to load the bases for Drew Stubbs, who flied out harmlessly to center field to end the game. [Canada.com]