Air plants are bromeliads, so they will flower and set seed. There are lots of species of Tillandsias, from tiny 1″ tall rosettes and the vining “Spanish moss” to species that just keep growing long thick stems. That large one was propagated simply by breaking off a piece of the stem with several leaves on it. They don’t need soil to grow in, but the foliage has to be misted a few times a week. Grayish scales covering the leaves absorb the water directly and distribute it over the surface of the leaf.