I mean this constructively.
PL (polarizing) filters are only useful over water, and/or highly reflective areas such as buildings with a lot of glass. ND filters are only useful for motion blur. That said, most often there is no need for a shutter speed twice the frame rate to capture motion blur. Sometimes, yes. Most times, no. This video has few vehicles, birds, or other moving articles. Therefore, there is little reason to concern yourself with motion blur, and an ND filter may not be necessary. I saw no reason for a PL filter
All of your flights appeared to be straight ahead, or up/down. If that is your preferred style, consider dedicating one of your customizable buttons to Auto Exposure lock. When you choose a direction, let the camera determine the exposure, then lock it in. If you change direction, unlock, and repeat this exposure procedure. If you want to adjust the cameras determination,adjust the EV +/-, then lock it.
I do think the atmospheric haze affected the background, but that's as it should be. That is a quality. Otherwise, be sure if it's cloudy that your settings are not on sunny because that will cool the image; excessively.
The only issue I saw with this video was the "judder". Spark video is smooth; generally. There are sections of this video where the motion appears to pass in steps like the truck at minute 1:05. It may be that the time frame of your edit is other than Spark' default 30 fps (29.97). If you don't want that (I find it distracting) be sure the time frame of your editor time line is 30 fps (29.97), and the video will become more smooth.
Hope this helps