To hightail is to leave or move very quickly. Your plan might be to hightail to New York City as soon as you graduate from high school.
Hightail is an useful, informal verb that means "get out fast" or "make a beeline for" or "cut and run." Bank robbers might jump in their getaway car and hightail it to their hideout, and a shivering snowshoer will hightail it to a warm fireplace after hours out in the snow. Hightail is 1890s U.S. cattle ranch slang, from the way a running cow or bull raises its tail.