Right. So that can be a pretty complicated answer. Or a simple one, if we were to make the operative word "might". Operative word "might"equals it's possible an age 5 typically developing wandering or lost child could have been missed under the prior search conditions. Assuming utilization of a night helicopter with specialized resources based upon a tip, one can infer that LE was looking for something indicative of heat or aggressive disruption of something on the ground that might produce heat, that sort of thing. In searches such as the video link above indicates, I'm going to guess that the ground (fields/farm/roadside/water in mid-June) were favorable for a helicopter to clear in a much more rapid fashion than ground searchers could do. So I'm going to assume that the helicopter was out ahead of ground searchers, hoping to find indication of something thermal or disturbed. Fwiw- that doesn't necessarily mean the missing child. Helicopters with specialized resources have been used for suspects, disturbances as small as footprints, smoldering fires, grow locations, vessels in water etc etc, sometimes in conjunction with a missing persons case. So there's that.
On the other hand, heavy and active (and sometimes chaotic) ground searches all during that time period- as well as at the same time that air search was being conducted- could really cause some problems with the effective utilization of those specialized resources. Yes, Summer is small in size, and it was estimated that she was wearing light clothing and was possibly barefoot, which would give SAR in the air an indication of what to look for in imagery. But with a lot of people on the ground...it would be difficult to adequately utilize those resources. Which is what had me initially wondering what exactly the tip might have been to basically try and utilize ALL of those resources simultaneously. If that makes sense.
I would be interested to know if the ground searchers were advised to be calling for Summer during that particular search. Might seem like a minor detail, but I actually think that might answer a lot of questions for us. This is all moo, of course.
ETA: Apologies, 1st response to question got accidentally cut off and also double quoted.