An air-filled or pneumatic tire consists of an inner core that is filled with pressurized air and sealed airtight. Typically, a reinforced steel belted tread or other materials, provides the contact area with the road and seals this inner core.
As the pressure of the air inside the tire is more than atmospheric air pressure, the tire remains inflated even with a vehicles' weight resting on it. The pressure of the air within the tire provides resistance against forces that try to deform the tire. This gives the tire a slight degree of a cushioning effect when the tire hits bumps in the road. If you have ever taken a ride in an old-fashioned carriage which had wooden wheels, you understand how big of a difference a set of pneumatic tires makes.
Pneumatic tires also come with disadvantages. High-performance situations or highly dangerous applications for example, these tires could suffer a puncture and this will lead to a total failure. The consequence of a blowout at high speeds can lead to a dangerous car accident. Military planners must consider tires getting blown out by explosion shrapnel or gunfire. The worst nightmare of a vehicle crew is becoming trapped in a fire zone because of all of their tires becoming flat. Airless tires obviously don't suffer from these problems and hence, in certain applications, can be more suitable.
Pneumatic tires have another issue involving variations in tire performance and air pressure. Lower tire pressure could create increased comfort and improved traction. This is due to the fact that tires flatten slightly and more tread is touching the road. The pressure of the air in the tire works to maintain the lateral stiffness of the tire as well as maintain the "up and down" stiffness. Hence, reduced air pressure allows the sidewalls of the tires to flex. Unfortunately, this leads to poor handling. Within an airless tire, the stiffness in those two dimensions is independent.
There are other issues with air pressure. Customers are notoriously undependable when it comes to maintaining correct air pressure. Tires which have wrong air pressure could lead to unsafe situations. It is essential to keep in mind that pneumatic tires are also susceptible to temperature changes, which could be responsible for changing the internal pressure of the tire. It is very important to consider the type of environments you will be needing your equipment to operate in so that you can regularly check the tires and keep the equipment as safe as possible.