No, solair feeding is way less important then soil feeding. As for soil feeding you feed the roots and they dispearse it qually throughout the plant. It's ok to solair feed but from my perspective just not worth i. If your going to do it do it at dark hours.
From what I know, the only things plants can absorb through their leaves are light, and air (a.k.a. CO2). However, misting the leaves, and maintaining a proper humidity level will help a plant retain moisture.