LSLGuy is right: contrails are, by definition, the visible trails due only to the condensation of engine exhaust. Although wingtip vortices may be rendered visible by condensation and/or dust, they are not called contrails.
LSLGuy is right: contrails are, by definition, the visible trails due only to the condensation of engine exhaust. Although wingtip vortices may be rendered visible by condensation and/or dust, they are not called contrails.