If you are referring to the needle-like rod or probe sticking straight out of a jet fighter's nose, it is not an "air breaker," but rather a Pitot tube (or a pitot-static probe/boom).  

​While it looks like a tool designed to pierce or "break" through the air, its actual functions are strictly aerodynamic sensing:

​Measuring Airspeed: The open end points directly into the wind, capturing ram pressure (total pressure) as the jet moves. Tiny holes on the sides of the tube measure static pressure (ambient atmospheric pressure). By comparing these two pressures, the aircraft's computer calculates accurate indicated airspeed, Mach number, and altitude.  

​Providing Unobstructed Airflow: Placing this sensor right at the very tip of the nose ensures that the data is gathered from clean air, completely free from the turbulence and airflow distortions created by the main body of the aircraft.

​Angle of Attack (AoA) Sensing: On many military fighter booms, additional vanes or ports are integrated to measure the angle at which the air hits the nose, helping the flight control system prevent stalls during high-g maneuvers.

​Why don't all fighter jets have them?

​If you look at modern stealth fighters like the F-22 Raptor or F-35 Lightning II, you won't see that prominent nose rod. This is because:  

​Radar Stealth (RCS): Protruding metal rods act like reflectors for enemy radar waves.  

​Flush-Mounted Sensors: Modern stealth aircraft use multiple flush-mounted pressure ports scattered around the fuselage combined with air data computers to calculate the exact same metrics without compromising stealth profiles.