Versione italiana
Your area of competence is divided into cells. Empty cells are identified by this symbol:
Empty cells that are situated on the main cardinal directions (N-S, E-W, NE-SW and NW-SE) are identified by special symbols.
However, not all cells are empty. Some of them contain hills:
or towers:
In this case, a number indicates their height. Planes that want to fly over hills or towers must fly at a quota higher than the obstacles' height.
There may also be restricted areas:
To fly over these areas is not dangerous, but since it is formally forbidden you loose points.
Finally, some cells contain airports:
A number identifies each airport; the direction of the arrow indicates the direction that the planes will have on taking off and must have on landing.
Moving from one cell to another there are two kinds of objects: planes and clouds.
Planes are of three kinds: jets
, propellers 
and helicopters 
. They are oriented to the direction they are currently heading, and their colour is darker if they are heading to their final destination. A number indicates the quota at which the plane is flying. A small danger sign flashes near the planes that are in a situation of danger, e.g. flying through clouds or over a restricted area or too near to another plane (nearly miss).Clouds are identified by this symbol:
and move in the direction of the wind, reported in the top-right part of the game window:
Planes and cloud positions are updated on the radar every 15 seconds. A countdown timer shows how much time is left before planes and clouds positions are updated:
Shouldn't you want to wait for the all 15 seconds to pass over before the radar is refreshed, you can click on the Skip button to immediately jump to the next round. You can also accelerate the time by a factor of 5 by checking the check button titled Accelerated Time.