The arriving airplanes normally come in from the north-west. If you stand at the Mataveri road leading to volcano Rano Kau you will have the airplane passing by just above your head, which is an impressive feeling. If you see a few vehicles by the road with people waiting you're probably in the right place.
There is approximately one airplane per day arriving to Rapa Nui. To find out what time the plane of the day will arrive you may ask at the LAN Chile office at Atamu Tekena (main street) or the local airport (phone: [+56 32] 2100 277), or check flight times at www.lan.com.