1. The problem asks why aircraft cannot travel faster than the speed of light. 2. According to Einstein's theory of relativity, the speed of light in vacuum, denoted as $c$, is the universal speed limit, approximately $3 \times 10^8$ meters per second. 3. The key formula related to this is the relativistic kinetic energy: $$E = \frac{mc^2}{\sqrt{1 - \frac{v^2}{c^2}}} - mc^2$$ where $m$ is the rest mass of the object, $v$ is its velocity, and $E$ is the kinetic energy. 4. As $v$ approaches $c$, the denominator $\sqrt{1 - \frac{v^2}{c^2}}$ approaches zero, causing $E$ to approach infinity. 5. This means that to accelerate an object with mass to the speed of light requires infinite energy, which is impossible with any known technology or physical process. 6. Therefore, aircraft, which have mass, cannot reach or exceed the speed of light because it would require infinite energy. 7. Additionally, traveling faster than light would violate causality and the fundamental laws of physics as we understand them. Final answer: Aircraft cannot go past the speed of light because it would require infinite energy due to relativistic effects, making it physically impossible.