The air-filled or pneumatic tire consists of a core filled with airtight sealed pressurized air. Usually, a tread made with reinforced steel belting or other materials, seals this inner core and provides the contact part with the road.
As the pressure of the air within the tire is more than atmospheric air pressure, the tire remains inflated even with the weight of the vehicle resting on it. The pressure of the air inside the tire gives resistance against forces which try 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 experienced taking a ride in an old-fashioned carriage which had wooden wheels, you know how big of a difference a set of pneumatic tires could make.
Of course, there are some disadvantages to pneumatic tires. Like for example in high-performance situations or highly dangerous applications, these tires could suffer a puncture and this will result in a total failure. The consequence of a blowout at high speeds could result in a serious car crash. Military planners need to take into account tires getting blown out by firing of guns or explosion shrapnel. A vehicle crew's worst nightmare is becoming trapped within a fire zone due to all of their tires becoming flat. Airless tires evidently 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 could create improved traction and increased comfort. This is due to the fact that tires flatten slightly and more tread is placed in contact with 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 sidewalls of the tires to flex. This leads to poor handling unfortunately. In an airless tire, the stiffness in those two dimensions is independent.
Air pressure factors into other issues too. When it comes to maintaining correct air pressure, consumers are notoriously unreliable. Wrong air pressure in tires can result in very unsafe situations. It is important to bear in mind that pneumatic tires are also prone to temperature changes, which could be responsible for changing the internal tire pressure. It is really vital to take into account the kind of environments you will be requiring your machinery to operate in so that you can regularly check the tires and keep the machine as safe as possible.