For starters, you have a good kit there. My first setup was a Nikon D50 with a 28-80mm and a 70-300mm. The 75-300 that you have will be good for stuff in the air. Depending on whether or not zoom lens has any image stabilizers, you can really get some good shots with a good amount of prop blur.
The general photography rule of thumb is to not go slower than 1/focal length. So if you are shooting at 300mm, the rule would be no slower than 1/300. The problem with that is obviously keeping track when using a zoom. So when I am shooting with my 50-500, I will typically shoot around 1/400, but may adjust for certain shots.
Keep in mind that is a general rule and when shooting digital, get outside your comfort box and try stuff you'd never do with film. The shots cost you nothing. Take a 300mm shot at 1/100, or 1/50. Practice panning technique by taking photos of cars moving.
Do 'kamikaze camera' (my favorite thing to do when bored at the airport, yes it does happen sometimes). Kamikaze camera is setting your camera on a basic setting like 1/250 with a standard lens, not a big zoom. Hold the camera out in front of you, or over your head, or at a weird angle and blindly take the photo. Most of the shots will be crap, but who cares? It's digital. Plus for every 30-40 crap shots play KC, you get something cool or interesting. This will help you break the 'film cost fear' of photography that makes you want to only take safe shots.
The 75-300mm will be a good start for your aerial shots. If you find yourself wanting more reach, you can start to look at 400, 500, 600mm lenses, but they start to go up in price quickly. The good news is that kit lenses will give you good shots, because like dogfighting, it ultimately comes down to the shooter as to how the shot is. You can perfect your technique with the 75-300mm and get some great shots while sparing your back and arms the burn of holding a 5-7 pound lens up in the air and following Rob Harrison, or Doug Jardine through an entire aerobatic routine.
I took, and used, the 50-500mm to Chino. A majority of the shots that I took ended up being around 300mm. It depends on the show, and your position on the showline as to how much reach you need. It also depends on what other photography you do as to your lens needs.
For filters, UV filters are nice for protecting your lenses from damage, and I know many photographers swear by them for that reason alone. You are going to have to experiment with them to get a feel for when they are useful. I personally never use them since I have switched to digital. I do all of my filtering in Photoshop. Filters can help enhance a photo, but also keep in mind that filters also give you one more shiny surface for light to get through, or bounce around and reflect.
I got a bad UV filter for my 50-500 that caused my images to be very soft. I bought them together and I almost returned the whole kit because I thought I had a bad lens. Then I thought to remove the filter first and take some test shots. It was a night and day difference. I'm not saying that all filters are bad by any means. I used them a lot with film. I just have a much different method of processing today.
Questions? Feel free to ask. Try different settings, play around and shoot with wild abandon. The ones that don't turn out you can always delete. One last thing on that. Never delete any shots during review on the camera. I have had shots that look so-so on the camera screen that looked REAL good on the big screen at home. Conversely, I have had shots that looked great on the little screen that were not so good on the big screen. The key is to look at all of them, good and bad. Looking at good ones lets you see what you did well and your composition. Looking at the bad ones are good to learn what you did wrong.