Based on the provided reference, the question is slightly misleading because it implies that the fastest aircraft overall is a fighter jet. However, the fastest aircraft on the list is the NASA X-43, followed by the NASA X-15, neither of which are fighter jets. Instead, the Lockheed SR-71 Blackbird is the fastest operational jet, which was built by the United States of America (USA). Though it's categorized as a strategic reconnaissance aircraft rather than a fighter jet. The fastest fighter jet on the list would be the Mikoyan MiG-25 Foxbat which was built by the USSR (Soviet Union).
Here's a breakdown based on the reference:
| S.no | Aircraft | Country |
|---|---|---|
| 1 | NASA X-43 | USA |
| 2 | NASA X-15 | USA |
| 3 | Lockheed SR-71 Blackbird | USA |
| 4 | Mikoyan MiG-25 Foxbat | USSR |
The list is not entirely of fighter jets, but contains the fastest planes in the world.
Therefore:
- If considering the fastest overall aircraft, the USA is the country that developed the top 3 fastest aircraft as per the list: the NASA X-43, NASA X-15 and Lockheed SR-71 Blackbird.
- If considering the fastest fighter jet from the list, the USSR (Soviet Union) is the country which created the Mikoyan MiG-25 Foxbat.
It's important to note that the provided list doesn't exclusively contain fighter jets.
