I have some air plant fertilizer that I received with some air plants that I bought. It is 16-9-24 and it's in a little spray bottle. Would this be good for a phalaenopsis orchid as well?

What are you calling an "air plant"? Just curious. Do you mean a Bromeliad by chance?

Anyway, the fertilizer you have could be used in a pinch but long term, I would recommend an even strength fertilizer like 18-18-18 or 20-20-20. For a Phalaenopsis, that is what I would use.
Just keep in mind that orchids do not need a lot of fertilizer. It really doesn't do the orchid much good but it makes you feel better. Fertilize your plant once a month at half strength. No more, not more often. The orchids can only use so much food, you would essentially be pouring your money down the drain.

Good advice, Bill. And in the winter I stretch it out even further between feedings

I fertilize once a year, in spring, with Dynamite 13-13-13 time release. That's it.

Your air plant fertilizer will be great for orchids as well.
MSU formula for orchids is 13-3-15 which the university has determined to be best for orchids, it also includes calcium and magnesium which you will probably be getting from your tap water anyway.

Thank you everyone for your responses and advice.

It all depends on what you're growing, and where you're growing it . We all grow different orchids in different environments, so watering and fertilizing are different for each of us. Trial and error, until you find what works best for you.

Out of curiosity, I would like to ask from what I have read i should use rain/distilled/RO water rather than tap water in my area since my city's water is hard (total grains per gal 10.5) and the Ph of 9.47. Both of the parameters from what I've read are not well tolerated by orchids. Is that correct?

I believe so, yes.

I use rainwater pretty much exclusively, for sure now 100 % during the indoor season in my greenhouse, and in Summer I use tap water only when I am out of town and using the sprinkler on a timer.

I use rainwater exclusively also now. I used tap water exclusively for about a year though with no issues.
Ph 9.7 is not good, mine is around 7 so you should avoid using that water @Cluelessmidwestern.
Orchids will not absorb certain nutrients as well when the Ph is that high.
If links work here follow this one to a graph explaining Ph and nutrient uptake.
https://www.finegardening.com/...

May I just chime in here to say I think your pH reading of 9.47 for your tap water is not right. Impossible they would let water from your tap be that high.

Our tap water here is somewhat hard, and alkaline too but the water treatment plant doesn't let the pH go higher than about 7.6. Our well water, straight from the limestone aquifer, untreated, comes in at around 8.2. You can test your tap water yourself using a swimming pool test kit to get an accurate reading. Or take a water sample in a ziploc bag to any pool store for testing.

I imagine the pH in well water from areas with alkaline sources could be that high but it certainly sounds unusual.

Doesn't get a lot more alkaline than a limestone aquifer, like we have under most of Florida.