Upgrades possible? Memory and SSD

The new '13 MacBook airs have soldered DRAM memory as such you can't upgrade it (just like the older Airs and the MBP retina models)

As to the SSD, yes it is removable, but Apple has changed things still again (I'll admit for the better here with a faster I/O over SATA III).

Apple now is using PCIe based SSD's. But they are using an interface which has not been finalized by the standards committee yet so its hard to tell if Apple's jump will be followed by others or are they waiting for the standard to be approved.

If the new M2 Standard is approved as is (no alterations) then other options will be coming in the next 6 months or so. Even if the standard is altered it's likely a 3rd party vendor will step forward and offer options. It's just a question of time.