GrammarDrive(tm) is a revolutionary new method of propulsion designed by GrammarNazi Limited. Although the time-flow of the multiverse ensures that nothing is ever revolutionary or new, GrammarDrive is nonetheless used by Grammar Nazis.
GrammarDrive functions through the correction of grammar. When grammar is corrected, the reportions pertaining to that are stored and used to power the drive. Corrective scout ships use a higher version of GrammarDrive, known as EverythingDrive, which runs on correcting anything.