I have noticed quite a useful fact over the last few years of growing phalaenopsis orchids concerning aerial roots. Whilst these roots are very necessary when the plants are growing from tree limbs in the wild, in the home environment they do not seem to be that useful.
My plants that had aerial roots still have them however and I mist the roots with rainwater once a week.
Plants that did not have aerial roots to start with have never grown them under my growth conditions and the keiki that I removed and is now a mature plant does not have any aerial roots. Nor does the second keiki which is still attached to its parent plant and is flowering at the moment, as is its parent.