You can also get computer fans that run off of AC, usually they are sold as fans for tanning bed machines, etc. I used one when I built my own laboratory equipment when I needed a 5 liter Erlenmeyer flask when I was growing yeast cultures for my yeast library back when I was seriously into brewing so you can find definitely find them out there if you really must have an AC variant. I am vaguely sure I bought that particular one from eBay at the time. AC will have more torque than the DC which I needed to move 5 liters of liquid with a bar magnet stirrer but either can be hooked up to a controller of some sort, whether you drive AC directly or DC indirectly through a transformer/wall wart its the same principle in play. I wouldn't fuss the details and end up in "analysis paralysis" as getting started is the most important step to completing any project. Moving air you don't need as much torque in play, if you want higher volumes then squirrel cage fans is what I used when moving large volumes of air against restrictive HEPA filters when I build a laminar flow hood for sterile mushroom cultivation. Either way just get started, the folks here will help you out if you run into any issues.