Something in the air

Am I imagining things or have the last few weeks been a cacophony of noise in the mornings? The novelty of change has become the sad inevitability of planes flying overhead virtually every morning out here in Daegu. In about three and a half years here, the last few weeks have been vastly different from previous times. I don't know what is going on. Has there been a new air base developed? I don't know the answer but I cannot help get the feeling that someone is preparing for something. Daegu has an airport and I can safely say that the noise is not coming from commercial airline flights. I wonder if this is happening just in Daegu or other parts of Korea.