Fly, dart, float, skim, scud, shoot, sail are comparable in their extended senses when they mean to pass, or less often to cause to pass, lightly or quickly over a surface or above a surface.
Fly (see also ESCAPE 1 ) may be used to imply movement through or as if through the air that suggests swift passage, buoyancy, or lack of impediments like that of a bird or airplane.
Dart in its extended intransitive sense implies movement that is as suddenly initiated and as straight and as swift in its course as that of an arrow or javelin.
Float in its extended use implies a buoyant and seemingly effortless gliding through the air or along a smooth or liquid surface.
Skim in its extended use implies a passing lightly and swiftly over the surface of something, sometimes darting into it, sometimes floating above it; often it suggests a light touching of the surface without real physical or mental penetration.
Scud implies light, rapid movement (as of a hare pursued by hounds, of a sailboat driven over the surface of the water by a high wind, or of clouds driven by an approaching hurricane); often, also, it connotes swiftness so great that the surface is barely touched by the speeding object.
Shoot differs from dart, its nearest synonym, in throwing less emphasis upon the suddenness of start and, often, in more definitely suggesting continuous or extended movement.
Sail differs from its nearest synonym float in more frequently implying power, ostentation as if of spread sails, or steadiness and directness of course.