yes of course you can pillar I do it all the time except I use dair instead of fair at low percents
if you are using strictly fair I would say it is more like a psuedo pillar because when you get them to higher percents it is highly dependent on how they di because if they di away then it makes it much harder to connect the followup fair after knocking them up with the u tilt
this is why dair serves better than fair for the purpose of performing an actual legit pillar where the whole point of it being that it is much more difficult for them to get out of because it is just way easier to catch them with dair than trying to connect with a laggy slow as hell fair against a falling mid air di'ing opponent, imo dair is just way more intuitive to connect with against di mid air opponent
fair is a great way to finish the combo with though and proceed into some non pillar type follow up, its making more work for yourself trying to pillar with just fair when you could use dair instead which is way harder to whiff with than fair, fair is 74 frames length and hits on frame 18 whereas dair is 38 total frames length and starts hitting on frame 10
I guess for me part of it is also that I still mess up the l cancel sometimes when I full hop fair so I find it easier to just remain short hopping and lunge with horizontal momentum so I can catch them at a sharp angle with a dair that I still only short hopped with (in instances where they are at higher percents and are di'ing away), hope that makes some sense
but yeah at midrange to higher percents you can totally pillar with fair if you are good at connecting your fairs with falling di'ing opponents, I just have an easier time using dair against good di because you can compensate for their di by overshooting the dair a bit with horizontal momentum when you see that they are di'ing away
at lower percents I find it difficult to pillar with fair because I find myself having to retreating fair sometimes in order to connect which makes it easier to mess up for me, this happens to me when I try to sh fair them when I'm too close to them underneath after the tilt as they're about to hit the ground, I often send myself forward a bit when hitting A to make the fair come out so I do a small sh retreating fair to compensate otherwise I overshoot unnecessarily, and so I mostly use dair for that reason but retreating fair looks cool and is great for stylin on them hehe xD
like I know the last two paragraphs sound like a contradiction but it really does come down to whether they di or not and choice of move for ease of trying to stay on them when they do di, a persons di really is the biggest factor that keeps me from fooling around with trying to throw out fairs when I'd rather just use dair and more reliable for me
but yeah try out dair and see what you think I'm sure you will like it once you see how it feels, whats also fun is you can somewhat pillar with the down b tornado move after l cancel fair or dair but, as usual, at higher percents can be harder to follow up depending on their di
edit - ok well I cant help but need to edit because I took a sec to try some stuff in training mode it appears that one could create true pillar by always connecting with fair on a falling opponent so as to always be thrown into the ground to be comboed off of which dair doesnt do dair has to be short hopped to function as pillar, full hopping dair lets you do other things like falling up air or nair or cape etc, but if you set the ai to jumping and can always catch him when hes falling and prevent him from jumping of his own accord then you know you're doing it right, I can do it reasonably well when I connect by short hopping it but full hopping I guess im not used to full hopping my stuff yet so I suck at it, but short hopping it is pretty cool though I guess having to full hop becomes necessary at higher percents which brings greater risk of them getting a tech before you land so it seems true pillar comes from short hopping it as much as possible, dair is great for racking dmg at low percents when the tilt doesnt throw them too far away for you to keep hitting them with dair over and over again before they can begin to di the tilt
