Narrow Runways
If you are approaching a runway for landing that is narrower than you are accustomed to seeing, you will experience the illusion of being too high. The smaller looking runway is interpreted by your mind to be farther away than it is in reality. The pilot has the tendency to fly a lower than normal approach, in an attempt to make the runway look normal. This could place the aircraft in an unsafe proximity to terrain and obstructions.
On landing, the pilot may have a desire not to level the airplane for landing at all, being surprised when the wheels suddenly strike the ground.
Wide Runways
The opposite is true on a wider than normal runway, which creates the appearance of being very close with its large size. Pilots have the tendency to fly high and try to level the airplane for landing when still at a considerable height.
Upsloping Runways
If the runway is sloping upwards, it creates the appearance that you are descending to the runway at a steep angle. This creates the desire to fly a low, shallow approach in an attempt to make the runway look like one that isn't sloped. A low, shallow approach is dangerous, since it could place the airplane in unsafe proximity to terrain or obstructions. Additionally, flying a shallow approach places you in a position where you would be unable to make the runway if your engine should suddenly fail.
Downsloping Runways
If the runway slopes downward, it will appear as if you are coming in at a shallow angle. This creates the tendency to fly high.
Featureless Terrain
Featureless terrain is a very hazardous and visual illusion. Pilots are used to seeing the ground move below them, giving visual altitude cues. At higher altitude, these cues go away. Pilots unconsciously associate the lack of these visual cues to mean they are at altitude. There are a lot of atmospheric and terrain conditions that can create a featureless visual field. For example, descending to land at an airport near a shoreline. A lot of accidents have happened when visibility is somewhat restricted at night in rural areas. The common picture is the pilot seeing nothing but the approaching airport.
Not receiving these visual warning clues that the airplane is getting too close to the ground, the pilot will simply descend into the ground. The pilot is completely surprised upon impact with terrain or obstructions. The lucky ones come away with some dings on the airplane and a few branches stuck in the gear.
Make sure you follow airport lighting systems that provide you with vertical guidance to the runway. Follow instrument indications. Situational awareness includes awareness of your altitude, the airport elevation, and the elevations of surrounding terrain and obstructions as you make your approach.
Be very careful when descending into an airport surrounded by featureless terrain. Controlled flight into terrain is the number one cause of aviation fatalities.
Haze
Haze creates the illusion of being at a greater distance from objects on the ground and in the air.
Night Landings
Inexperienced pilots often have a tendency to make approaches and landings at night with excessive airspeed. Pilots must be aware of this tendency and concentrate on making night approach and landing in the same manner as during the daytime.