Will my MacBook Air 6,1 support MST (Multi-Stream Transport)? I have an 11-inch, Mid 2013 MacBook Air. I'm wondering if I can hook up two Dell U2417H monitors using the DP out port on the monitor. So DP from MBA to first Dell U2417H. Then DP to DP from first U2417H to second U2417H. Is this possible? The display is not 4k.

Edit: I realize this question might have been asked, but the one I have found is asking about 4k.
Your MacBook Air's hardware: Yes.
MacOS (as tested with macOS Sierra 10.12.6): No.

I've tested it myself with an older MST capable Dell monitor and found various forum entries about this topic. No chance with macOS.
The Intel HD5000 graphics chip on your Macbook is capable to do MST with DP 1.2.

MacOS does not have any MST support built in. There is a 1% chance it will work with High Sierra 10.13 (if somebody can test this?!) but I really doubt it because Apple does not care about daisy chaining with MST when they have their Thunderbolt ports (which require a Thunderbolt monitor).

Only way to get MST working may be using a native Windows installation with Bootcamp on your Macbook.