Note: Contrails are not produced by gravitic craft for two reasons: first, unlike jet aircraft, gravitic craft have no exhaust to speak of, and therefore release no steam nor particulates to trigger the desublimation of moisture present at high altitudes. Second, unlike fixed-wing aircraft, gravitic craft do not have wings to create wingtip vortices, which in turn means that there are no low-pressure vortex cores in which atmospheric moisture can precipitate.

This is not to say that gravitic craft NEVER create contrails. Indeed, in rare cases they do leave contrails -- usually because they are leaking particulates from a cabin rupture. This sort of contrail is typically quite short, however, terminating in a more pronounced debris trail, airburst fireball, or maybe even a nice patch of lithobroken ground.