After finishing with the perspective match, place the drone in position and then create a plane underneath it. Create a Corona Shadow Catcher material in the material slate and attach the environment image to the backplate and apply the shadow catcher to the plane.
Use either an HDRI or a Corona Sun for the lighting to do this, replace the background image with the HDRI or a Corona sky (if using a Corona sun) and place it in the same location where the light is coming from in the background image. I personally used a Corona Sun in this image as I couldn't find a HDRI which gave lighting or shadows that I thought fit with the image. To get the Image being used as the background, back as the background after replacing it with the HDRI, go to the render set up, scene then down to direct visibility override and place the image in the map area where it says none.
Before rendering out the image, go to where the shadow catcher material is in the material editor and change the alpha mode to "for compositing" and go back to the direct visibility override in the render set up and untick the box on the right next to the map so that the background will appear black. Also apply a ambient occlusion in the render elements.
Make sue the image size is the same as the original image being used as the background and then render the image out.
