Well, let's see...
Not sure what you mean by "pre-oxygenate." Are you referring to bubble in a resevior, then pumping that water to buckets? There might be O2 loss along the way; bubbling in buckets has proven itself effective. I wouldn't worry too much there.
About the difference between DWC and aeroponics, if that's the question...
It's probably not so much small droplets necessarily but the ratio of droplet size to the amount of air the roots are exposed to. In other words, I've read that we can get about an 8% oxygen boost by bubbling in DWC, but since regular air has about 20% oxygen, if you can expose your roots to normal air they end up getting more oxygen exposure, believe it or not. So this is probably way aero seems to work so well, however, it might create a grow environment where you've got to really watch your details (pH, ppm, temperatures, etc.) because people say that one slip-up in aero and you're going to cook your plants. In my opinion, the best way to combine the two (and perhaps this is what you're thinking of doing), and that would be to grab outside air by using a small stream of water that run down into a bucket. For example, you take a 5 gallon bucket and put not an air pump in the bottom, but instead use a water pump and hook it up to plumbing that carries water up to through the top and run it back down into the bucket by free-fall or run it over the stones, the hydroton. Use a big enough pump, which would be much for such a small application, and the splashing effect would add oxygen into the water/nute mix. There's a name for this method but can't remember it right now. What would be even better is to do that but place a sprayer to two just under the lid which would for water to take up even more oxygen on its way back to the bottom of the bucket. At any rate, I'd just stick with DWC and an air pump because it works and its so little trouble. As far as bubbles popping at the surface this is pretty irrelevant as it's really the air pump that puts oxygen in the water. You want your roots to get down into oxygenated water using DWC. In aero the roots tend to be suspended in open air and get a water/nute mix sprayed on them. If you really want to mix the two, then a drip ring method might be for you.
polishpollack Reviewed by polishpollack on . DWC aeration question Note: I am not looking for opinions, but some botanical science, if possible. From early readings on DWC, many people proposed that the air bubbles oxygenated the roots, thus speeding growth. Then from later readings on aeroponics, it appears that maybe the bubbles bursting at the surface create a nutrient mist that is more easily absorbed by the fine root hairs. Or perhaps it is both. If the former truly has an effect, then pre-oxgenating the feed water for passive hydro (ie: Hempy Rating: 5