Why Planes Don’t Ascend, Wait, and Land to Save Fuel

Many people wonder why aircraft don't simply ascend, wait for their destination to catch up, and then land, saving vast amounts of fuel in the process. This article will answer why such a strategy is impractical, explain how aircraft operate relative to the air and Earth, and discuss the impact of Earth's rotation and atmospheric conditions.

Understanding Relative Airspeed

Aircraft fly according to the air in which they fly, not the Earth itself. The Earth rotates at approximately 1,000 mph at the Equator, but the air also moves with this rotation. Imagine a fly inside the plane with you; the fly doesn’t need to fly as fast as the aircraft because the air carries it along with the rotating Earth. This is the concept of relative airspeed.

The Role of Atmospheric Rotation

Our atmosphere is not a static layer but rotates along with the Earth. If the atmosphere did not rotate, the immense winds resulting from Earth's rotation would sweep everything off its surface. This rotation affects not only the plane's flight but also all objects on Earth, ensuring that they maintain their position relative to the Earth's surface.

Practical Considerations

Some argue that if the Earth rotates at 1674 km/hour, planes could simply ascend, wait, and then land. However, this is incorrect. The 1674 km/h is the linear speed at the Equator, and even this is relatively slow compared to the Earth's rotational speed of 7.2921159 × 105 radians per second. This is incredibly slow, as it's only half the speed of the hour hand on a clock.

Additionally, the atmosphere effectively carries aircraft along with the Earth's rotation. Planes cannot simply "freeze" in place because the air in which they fly is also rotating with the Earth. Attempting to "freeze" in place would not work, as the air would still move with the Earth, leaving the plane stationary relative to the Earth's surface. This applies to all aircraft, including helicopters, which also travel at the same relative speed as the air around them.

Flying Routes and Speeds

Strategies like waiting for a location to rotate into position would only work for flights heading in a perfect east-west direction. For example, flying from Houston, TX, to Chicago, IL, an eastward route, would not benefit from waiting for the destination to arrive, as the destination would simply move further east. Similarly, flights heading in other directions, such as north-south, would face challenges due to the curvature of the Earth.

Conclusion

Aircraft, whether planes or helicopters, cannot simply ascend, wait, and land to save fuel. This is due to the air's movement relative to the Earth and the impractical nature of trying to "freeze" in place. Planes and helicopters must navigate the atmosphere, which is already carrying them along with the Earth's rotation. Understanding this dynamic allows for effective and safe air travel.