A Greek fighter jet crashed into a Turkish warplane over the Aegean Sea this week, killing the Greek pilot. The Turkish pilot ejected safely. The two jets were apparently engaging in a mock dogfight, something both air forces do routinely in an often-tense test of wills. Greece says its national airspace extends 10 miles into the sea, while Turkey recognizes Greek airspace for only six miles, the distance of international territorial waters. The two rival countries, both members of NATO, have come close to war three times since 1974 because of disputes over territory.