### Instruction: What would be the pros and cons of replacing all civilian airplanes with dirigibles?
### Response: Replacing all civilian airplanes with dirigibles would have positive and negative effects. The most notable positive effect would be reduced environmental impact: although dirigibles, like airplanes, need engines, dirigibles are filled with lighter-than-air gas and therefore no power is needed to counteract gravity, so they consume less fuel. However, there would be a significant negative economic impact because dirigibles fly much more slowly than airplanes, thus the items airplanes carry (e.g. people and freight) would take much longer to get to their destination. In addition, another problem with dirigibles is that they are less able to handle strong winds compared to airplanes, so it might be necessary for the dirigible to take a more circuitous route than an airplane, or simply delay the flight until the bad weather passes.