I'm also just beginning, and took an excellent class given by one of
the experts from the local orchid society. This class included everyone
getting an overgrown phal, with roots going everywhere, and repotting it.
The instructor (a past president of this group, who brought in fabulous
examples of things she's growing) indicated that we should stuff all the
"aerial roots" into the potting medium in the new pot, so that none were
sticking out when we were done. I gathered from this that the roots are
very adaptive, whether they're inside the pot or outside, and can take up
moisture and nutrients easily even if shifted from "out" to "in." Is this
incorrect?
Thanks for any insights here.

It's not incorrect if the roots will go willingly in the pot. It is most
emphatically incorrect if you have aerial roots which wholeheartedly resist
to the point of breakage. I think the key to the answer is a definition of
aerial roots. If a Phal is in dire need of repotting, it may have grown up
out of the pot, with roots showing. In that case, the roots are not truly
aerial, but simply exposed, so sure, they will go into the medium. Most of
us think of aerial roots as those which grow in an unruly fashion and do not
lend themselves to "going in the pot". For example, I have several Phals
with great roots in the pot and also long roots growing almost straight up
alongside the leaves. Those roots will never go into the pot.

Remember that whether the roots are in or out of the medium, they are of
value to the plant. So, when you water/fertilize, be sure to include any
aerial roots that are not submerged in the medium.

Welcome to orchids anonymous.........

Diana