UPDATE: as promised 2 days ago (on FryDee [Friday in proper English] March 15th) here is The Committee's update and explanation of the article:
Explains The Committee:
Mentioned in the article is the speed of light, specifically laser beams and photons of light.
Not mentioned: the speed to traverse great distances, by human Earth standards and perception of them, requires velocities vastly superior to 300,000 km/s. Incremental increases of such speeds, brought about through the use of planetary gravity, approach and slingshot style departures, do not achieve the required movement.
This method or technique is viable for use at far lower velocity than is used to cross significant segments of galaxial distances; within a system of planets, when navigating from one to another, this method can be useful.
Planets and their gravity are not used by interstellar travelers; this is achieved, as we have explained previously, with magnetism, magnetic fields and differences, much the way magnetic poles either repel or attract one another.
Joke time: (no Committee, just levity and because I feel like it)