Sounds like compressed plucked-bass samples. The EQ on the bass is interesting; sounds like a peak in the upper-mid range. I don't hear any LPF.

It does sound like they fed it through a highpass or bandpass filter, as the lows are lacking some of the frequencies. Definitely play with your EQ a little using the low end of the TB-303. And make sure to add a little pitch bending between some of the notes

Mmmm... yes, I would concur. This sounds about right.

They did a really good job with it too; very 70's disco like.

That's a TB-303 playing an acid line on its lowest octave possible.  It's a little compressed to make it really fat sounding.

Sounds like a real bass with lots of compression on top. If you want to synthesize it, your best bet is a single saw with a LPF. Same envelope on amplitude and filter: no attack, quick decay, sustain at 50% give or take, no release. They seem to have taken out a fair bit of the low low end too, so you might want to EQ that out so it hits around the low mids.

It's not really chip, but most people here seem to be pretty good at synths in general, so I thought it can't hurt to ask. There is something sort of airy about this bass tone, I can't figure out how they're achieving that sound..any thoughts?

Base starts around 0:40.