In short, yes – they can. That is if they are equipped with the appropriate technology flying into an airport which also has associated facilities. Today most commercial airliners and most major airports around the world possess each of these.
On a nice sunny day when pilots have a clear view of the runway they can manually fly an entire approach down to landing with no need for the autopilot. In many places around the world however, clear sunny days don’t always happen and in those situations the autopilot is utilised to bring the aircraft below the clouds.
This is done by the autopilot locking onto what’s called an Instrument Landing System (ILS) which guides the aircraft down along an invisible 3 degree slope to a point where the pilots can see the runway, take manual control and land the plane.
Sometimes however, the weather can cause visibility to become so poor that the runway is out of sight until just before the plane touches down. In these cases, most commercial aircraft can be programmed to fly an automatic landing (autoland) where the autopilot will land the plane and remain engaged until shortly after touchdown.
So if the plane can land itself why not let it do that all the time?
Well firstly not all airports (and not all aircraft) are equipped to facilitate autolands which means that some landings have no option but to be made manually. Secondly, if planes were to autoland all the time then pilots would become out of practice at landing the plane themselves (and no one likes an out of practice pilot).
So next time you’re on a flight that lands at a particularly foggy airport, chances are the plane did it all on its very own (under the watchful eye of two alert pilots).
Oh and no, planes can’t takeoff automatically.