Digital manipulation of video

[Dave Keen]

Hello!

I'm making a short film set in 1938 Spain in the civil war. I want a drone shot rising from eye level on a group of people crossing a bridge to a wide shot at about 70 feet altitude.  I want to remove some cellophone towers and add some distant houses, (distant because of the altitude) some houses bombed out and incomplete, some smoke. 

How can I remove objects and add objects to the moving image? I see it in movies but I don't know how to do it. I use FCPX but I could also do it in Premiere Pro or DaVinci if there were no choice.

 

Thanks!