The X-15
Because it is travelling faster than the speed of sound, the sound comes later. However, if a fighter plane was slower than the speed of sound, you'd see the plane first.
The first plane was the experimental Ball X-1.
The first such plane was the experimental Bell X-1.
There was not a special name for the first flight that went faster than the speed of sound. However, when a plane does go faster than sound, it said to be traveling at supersonic speeds.
You would hear the sound after the plane has passed.
The Concord's speed was 1,176. Faster than the speed of sound
No, the Tupolev Tu-144 was the only other commercial plane to date to fly faster then the speed of sound.
Concorde
That is called "supersonic".
As altitude increases (to about 35,000 ft) air density, pressure and temperature all drop. As density decreases speed of sound increases, but with drop in pressure it drops; these two practically cancel each other out. As temperature drops, speed of sound drops. Thus at 15,000 ft the speed of sound is slower than at 6,000 ft so plane X is flying faster than plane Y.
ultra sonic !!
when the plane goes faster than the speed of sound then the plane is seen first and the sound is heard after the plane has passed away. In this case the plane is having speed more than 1 mach.