The foundations for faster air travel were laid when American aviator Wiley Harderman Post was credited with discovering the jet stream (in a search for the equatorial smoke stream phenomenon that was mapped by weather watchers after the 1883 eruption of Krakatoa and detected by Wasaburo Oishi in the 1920s using pilot balloons released near Mount Fuji). (Source)
On an experimental high-altitude flight on 7 December 1934, Wiley manoeuvred his aeroplane into a fast-moving air current, resulting in a significant increase in ground speed. The discovery proved a pivotal moment in aviation history, as it opened the door for high-altitude, ultra high-speed air travel.
As a memory refresher, jet streams are super fast flowing, narrow air currents found in the atmospheres of some planets, including Earth. (Wikipedia) While the speed is dependent upon the disparity between colliding warm and cold air systems, jet streams, which typically occur between 7 and and 16 km above the earth, have been recorded as flowing at a speed that is anywhere between 90 and 400 kph. Planes that take advantage of these streams and the force they provide can fly much faster and further than planes that don’t. For most of the year, there are two sets of distinct jet stream systems in each hemisphere of Earth: one at the pole and one at the sub-tropic, and that’s why many inter-continental flights take these routes.