When flying from Killeen to Cartagena, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
GRK stands for Killeen Fort Hood Regional Airport, while CTG stands for Cartagena Rafael Nunez Airport. These codes are often called IATA codes, a set of identifiers established by IATA (International Air Transport Association) that is widely used by airlines and the aviation industry.