Question: Southeastern Airlines was acquired by a carrier of what regional airline that operates short and medium-haul routes?
Sentence (from "Cathay Dragon"): Hong Kong Dragon Airlines Ltd (Chinese: 港龍航空公司), operating brand as Cathay Dragon (Chinese: 國泰港龍航空) and previously as Dragonair, is a Hong Kong-based international regional airline, with its corporate headquarters, Cathay Dragon House, and main hub at Hong Kong International Airport.
Relevant evidence: No