From Fallen London Wiki

I did find one use of this on my flights between london and the first (and currently only) stop on the roof, but I didn't think to record what exactly it was. I think it was dodging criminals who'd stolen a dirigible to get out of New Newgate, or something to that effect. It was aerial prowess + insubstantial, so I can confirm it's a neathproofed-esque stat.