Although mapping a whole mountain in an afternoon is pretty cool, I don’t think three drones constitute a “fleet,” as the article puts it. But this raises the interesting question of what the collective noun for drones might be. There are enough of them around these days to merit such an honorific.
Examples from nature range from the alliterative (gaggle of geese) to the evocative (pride of lions) and the downright strange (murder of crows). So how about a “draft” of drones? I like the connotation with drawing or pulling since drones often do both, whether shouldering a load or mapping their environment.
“The Matterhorn was mapped in six hours by a draft of drones that launched from the summit.” Hmm, that has a nice ring to it.