From the announcement:
In March, we announced the upcoming release of two SSU airborne units for Dust Tactics and Dust Warfare: the SSU Airborne Walker Transport and the SSU Ground Attack Helicopter. At the time, our intelligence assured us that these helicopters would be combat-ready by the end of June. So, where are they?
Minor production issues delayed the release of these two helicopters, but the problems have now been resolved. The helicopters are truly combat-ready, and we will begin shipping them shortly. They should be available in stores in a little over a month.