Delta Air Lines Inc. placed a $320 million order for 40 airplanes equipped with engines made by GE Aviation, the Cincinnati Business Courier reports. The order for 40 Bombardier CRJ900 regional airplanes powered by CF34 engines includes an option for an additional 30 aircraft. Evendale-based GE Aviation, a unit of General Electric Co. (NYSE: GE), is the world’s largest manufacturer of jet engines. Delta (NYSE:DAL) is Port Columbus International's second-busiest carrier with nearly 1.3 million…