Drone-based inspection systems provide a rapid and efficient method that can drastically reduce both inspection time and costs. Drones equipped with optical and infrared (IR) cameras have been employed in various surveillance and monitoring tasks. In the realm of aerospace structure inspections, the use of visual cameras on drones is advancing more rapidly than passive infrared thermography with onboard IR cameras. This is because effective passive IR inspection requires thermal contrast between the inspected component and the background. Passive thermography falls short for detecting hidden defects such as water ingress, impact damage, delamination, etc. For detecting hidden defects, active thermography is more appropriate. This technique requires an external heat source to create the necessary thermal contrast to detect defects. Adapting or developing an active thermography system for drones is challenging and necessitates integrating a heat source that is both powerful enough to meet the active thermography inspection requirements and lightweight enough to fit the drone's payload and power limitations. Additionally, the cooling effect from propeller downwash needs to be considered. Therefore, this paper explores a drone-based thermography inspection system, focusing on selecting an appropriate heat source and accounting for the cooling impact of propeller downwash. Experimental results are provided to demonstrate the effects of both heating and cooling, offering insights into the drone-based infrared thermography inspection system.