[robotresearcher]

Adding detail to leetcrew's good reply: the energy of an aircraft in flight is proportional to the square of its velocity. Given steady progress in plane technology you'd expect practical top speed to be limited by cost of energy before too long. That happened more than thirty years ago.

[jasoncrawford]

Unless we also had progress in energy technology that could overcome this, which unfortunately we haven't.

[robotresearcher]

You can't make something cheap enough to overcome quadratic growth in demand for very long.

Not even CPU cycles.