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The reading passage states that airships, once an important transportation mode, will gain popularity again due to their advantages compared with airplanes and helicopters. However, the professor in the lecture casts doubt on the idea by saying that it is unlikely that airships will be widely used in the future.
First, the author asserts that airships are more economical in terms of fuel costs because they use less fuel than an aircraft. On the other hand, the speaker refutes the point by stating that it is not an easy task to find a truly economical solution for the lifting gases which can balance safety and cost. Airships require special lighter-than-air gases to give them lift. The two most efficient lifting gases, hydrogen and helium, have their own problems. Catching fire easily, hydrogen has caused airship accidents in the past. Helium is safer, but it is difficult to get, expensive, and it cannot provide as much lifting power as hydrogen.
Second, the writer claims that airships can be used in hard-to-reach locations because they do not require a long runway for takeoff and landing and can carry heavy loads. On the contrary, the professor disagrees with the belief by pointing out that using airships for picking up loads off the ground has its challenges. When an airship picks up tree logs in a forest, it has to slowly come down, pick the logs up, and then safely rise again. In this process, it has to be kept steady so as not to crash. However, an airship is large and light, which makes it difficult to keep it steady. A sudden wind can blow it against the surrounding forest trees and damage it.
Last, the author contends that airships can be used to replace satellites for telecommunications or surveying purposes with lower costs. Nevertheless, the lecturer refutes the idea by arguing that right now airships are not ready to replace satellites. Currently, airships in use can only rise to about 14 kilometers above the surface. The problem is that there are strong winds at that height, so they have to spend a lot of fuel to resist winds and stay in one place to carry out telecommunications or surveying functions. Then, they will quickly use up the fuel and have to refuel. Therefore, right now they cannot provide the same kind of continuous, uninterrupted service as satellites can.