An air-filled or pneumatic tire is composed on an inner core which is filled with pressurized air and sealed airtight. Usually, a tread made with reinforced steel belting or other materials, provides the contact area with the road and seals this inner core.
As the air pressure inside the tire is more than atmospheric air pressure, the tire remains inflated even with the weight of the vehicle resting on it. The air pressure in the tire provides resistance against forces which attempt to deform the tire. When the tire hits bumps in the road, this gives the tire a slight degree of a cushioning effect. If you have ever taken a ride in an old-fashioned carriage that had wooden wheels, you know exactly how big of a difference a set of pneumatic tires makes.
Pneumatic tires also come with disadvantages. Highly dangerous applications or high-performance situations for example, these tires can suffer a puncture and this will result in a complete failure. The consequence of a blowout at high speeds could result in a serious car accident. Military planners need to consider tires getting blown out by gunfire or explosion shrapnel. The worst nightmare of a vehicle crew is becoming trapped within a fire zone due to all of their tires becoming flat. Airless tires obviously don't suffer from these problems and therefore, in some applications, may be more suitable.
Pneumatic tires have another problem involving variations in air pressure and tire performance. Lower tire pressure can create increased comfort and improved traction. This is due to the fact that tires flatten a little and more tread is touching the road. The pressure of the air inside of the tire works to maintain the lateral stiffness of the tire as well as maintain the "up and down" stiffness. Hence, less air pressure enables the tires' sidewalls to flex. Unfortunately, this results in poor handling. In an airless tire, the stiffness in those two dimensions is independent.
Air pressure factors into other problems too. With regards to to maintaining proper air pressure, customers are notoriously unreliable. Wrong air pressure in tires could result in very unsafe situations. It is essential to note that pneumatic tires are also prone to temperature changes, which can be responsible for changing the internal pressure of the tire. It is vital to consider the type of environments you would be requiring your machine to function in so that you can regularly check the tires and keep the equipment as safe as possible.