A landing strip is a small, narrow patch of hair that is left behind after a bikini wax. It is named after the long, narrow strips of asphalt that planes land on.
A wax with a landing strip is almost like a Brazilian wax, as the hair around the genitalia is removed, but it leaves a bit of hair at the front for aesthetic purposes. It also saves one of the most sensitive areas, the mound of Venus, from painful waxing.