An air-filled or pneumatic tire is composed on an inner core which is sealed airtight and filled with pressurized air. Usually, a tread made with reinforced steel belting or other type of materials, seals this inner core and provides the contact part with the road.
Since the air pressure inside the tire is greater than atmospheric air pressure, the tire remains inflated even with a vehicles' weight resting on it. The air pressure within the tire gives resistance against forces that 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 that had wooden wheels, you understand exactly how big of a difference a set of pneumatic tires makes.
Of course, there are several drawbacks to pneumatic tires. For instance in high-performance situations or highly dangerous applications, these tires can suffer a puncture and this would lead to a total failure. The consequence of a blowout at high speeds could lead to a dangerous car accident. Military planners need to take into account tires getting blown out by explosion shrapnel or firing of guns. A vehicle crew's worst nightmare is becoming trapped in a fire zone due to all of their tires becoming flat. Airless tires evidently don't suffer from these issues and hence, could be more suitable in some applications.
The pneumatic tire might have issues as well with the variation in air pressure and tire performance. The lower pressure inside a tire may increase the comfort level and the traction. This is because of the fact that tires flatten a little and more tread is placed in contact with the road. The air pressure inside of the tire works to maintain the "up and down" stiffness as well as maintain the lateral stiffness of the tire. Hence, less air pressure allows the sidewalls of the tires to flex. This results in poor handling unfortunately. In an airless tire, the stiffness in those two dimensions is independent.
There are other issues with air pressure. Consumers are notoriously undependable when it comes to maintaining correct air pressure. Tires that have incorrect air pressure can result in unsafe situations. It is important to bear in mind that pneumatic tires are susceptible to temperature changes also, that could be responsible for changing the internal pressure of the tire. It is very vital to take into account the type of environments you would be requiring your equipment to function in so that you could check the tires regularly and keep the machinery as safe as possible.