Update: I can land Neo's at 'Abdera' (NW Altis) in under 300m now.
See youtube from late 2016
https://www.youtube.com/watch?v=hvXr2tBnhxA&t=9s
Full explanation in there; it can be done (<300m) for a Neo landing : )

On KotH multiplayer/Editor, I land the Neo's on dirt at 380m (best effort) and avg 430m, based on a 'Waypoint' I use to mark touchdown.
Take off is about 400m. (depends if u have obstacles at end. Lift off at 200km/h)