1. (b) That's wrong. For the purposes of this tort, 'land' includes the land itself and also structures built on the land or things attached to the soil. It also includes the air space above the land (to a reasonable extent) and the earth below the surface (subject to mineral rights).
Trespass may involve entry to land or buildings; or tunnelling beneath the land; or erecting overhanging objects (such as signs or scaffolding). However, it would not include flying an aircraft over another's land (unless at an unreasonably low altitude).