I'm doubtful that the small gateways made by weak AS only big enough to get an arm through are on the ground. But I'm also doubtful that you can open a gateway to a place that has virtually no reference point or reference points too far away. Logain opened his gateways an inch above his reference point a gatgeway in the sky would be miles above any reference point and may actually be impossible. I know it is bizarre to think that a weave that connects two points far apart would have limits on distances but not so much when you considered that both descriptions of traveling require reference points and air all around you is not much of a reference point there is no diversity in the substance. I doubt even Logain could land at a specific spot in the ocean if he didn't have a ship as a reference point. the ocean being no more distinct to human senses that air.