I first came across aluminum sunglasses back in 2005 when I took over another online sunglasses business. I was instantly impressed by their durability and style, I mean I could drop them as many times as I liked and it didn't matter. If for some weird reason I managed to damage them I could get them repaired, which is more than I could say for the prescription Ray Bans I had from LensCrafters!
Currently there are only really two aluminum sunglass brands you should look at, Gatorz and Liquid Eyewear. There are other brands around however a number of them are all made in the same factory and sold under different brand names, quality control is poor and customer service is debatable. I know this from experience!
Gatorz are the original aircraft aluminum based brand. You'll find their shades right across the military (SEAL, Marines etc) to sports stars to Hollywood in Universal's epic war film Lone Survivor.
Liquid Eyewear are unique in that their frames have a hingeless arm design plus they offer a great selection of lenses and add on accessories. Which one you choose really just depends on what you need the glasses for and style preference.