2. They can hover over a particular point.
3. They can be noiseless by cutting off motive power and drifting for a while with the wind.
4. They can from their possible size have long range of action.
5. They can carry considerable weights.
6. They are endowed with sustaining power and stability.
1. Their speed can be variable.
This advantage becomes apparent in cases where they are used both for scouting and offensive purposes.
In a later chapter it will be pointed out that though the aëroplane scout has often to make dashes over the enemy, and it would be thought that from his swift movements his impressions might be vague, still, in practice, most satisfactory work has been undoubtedly accomplished. Many, however, will maintain that there are circumstances when it may be advisable for observers to proceed at variable speeds. When at a safe height it may be an advantage for the observers to take their time and leisurely survey the country, observe, and take photographs. The airship can stealthily travel over camp and fortress and steal secret after secret of the enemy.
2. They can hover over a particular point.
The fact that the maintenance of the airship in the air does not depend upon a certain speed being maintained, as is the case with the heavier-than-air machine, endows it with the property of being able to hover in fairly calm weather. The hovering power is certainly an advantage for such offensive operations as dropping bombs.