For decades, fighter aircraft seemed to be locked in a race to go faster.

Mach 1.5. Mach 2. Mach 2.5.

The numbers kept climbing.

Aircraft like the MiG-25 Foxbat were built around extraordinary speed, while the MiG-31 Foxhound could reach speeds of around Mach 2.8 under appropriate conditions.

So why don’t today’s newest fighter jets seem obsessed with breaking those records?

The answer is simple:

Because being extremely fast is no longer as useful as it once was.

Speed Used to Be the Advantage

During the Cold War, speed could provide a major tactical advantage.

A faster aircraft could intercept an approaching bomber more quickly, reach a target sooner, escape certain threats and potentially use its speed to control an engagement.

This was particularly important when countries were designing aircraft to intercept high-speed bombers and reconnaissance aircraft.

Speed was therefore a very visible measure of capability.

But aerial warfare changed.

Modern Air Combat Starts Before the Dogfight

Today’s fighter aircraft are increasingly designed around something more important than raw speed:

situational awareness.

Modern fighters combine radar, infrared sensors, electronic warfare systems, data links and information from other aircraft and ground systems.

The pilot may receive information about an enemy aircraft without even seeing it.

That changes the question from:

“How fast can I get there?”

to:

“Can I detect, identify and engage the enemy before they can do the same to me?”

In that environment, another few hundred kilometres per hour of top speed may provide less benefit than better sensors, electronic warfare or stealth.

Going Faster Gets Expensive

There is another problem.

Physics.

As an aircraft approaches supersonic speeds, aerodynamic drag increases significantly. The engines have to work harder, fuel consumption rises and the aircraft experiences much greater aerodynamic heating.

At very high speeds, the aircraft’s skin can become extremely hot.

This creates engineering challenges involving materials, engines, air intakes and weapons.

And then there is fuel.

A fighter travelling extremely fast can burn through its fuel surprisingly quickly.

That creates a nasty trade-off:

You can arrive faster, but you may have less fuel left when you get there.

Congratulations. You’ve won the race and arrived at the fight with an empty wallet. 💀

Speed Can Also Work Against Maneuverability

Modern air combat isn’t simply about flying in a straight line as quickly as possible.

Fighters need to accelerate, decelerate, turn, climb, descend and change direction rapidly.

That means the aircraft needs to manage its energy effectively.

An aircraft travelling extremely fast has enormous kinetic energy, but converting that energy into useful maneuvering without losing control or bleeding excessive speed becomes increasingly important.

This is why modern fighter design focuses heavily on the balance between speed, thrust, drag, maneuverability and energy retention.

Missiles Changed the Game

Perhaps the biggest reason is that fighters don’t need to be extraordinarily fast to deliver extraordinarily fast weapons.

A modern fighter can launch a missile that accelerates to speeds far beyond the aircraft itself.

So instead of designing a fighter capable of Mach 3, designers can build an aircraft with a more practical top speed and let the missile provide the extreme speed when it matters.

The fighter’s job becomes finding the target, generating a good engagement opportunity and launching the weapon.

The missile does the sprinting.

Stealth Changed the Priorities

Modern fighters also increasingly prioritize reducing their detectability.

Stealth aircraft such as the F-35 Lightning II are designed around reducing radar detection, managing infrared signatures and integrating sensors and information.

That doesn’t mean speed is irrelevant.

It means speed is only one part of a much larger system.

A fighter that can remain difficult to detect, understand the battlespace and launch weapons from an advantageous position may be far more valuable than an aircraft that simply flies hundreds of kilometres per hour faster.

So, Do Modern Fighters Have Top Speeds?

Absolutely.

Aircraft such as the F-15, Su-35, F-22 and MiG-31 are capable of very high speeds.

But modern fighter development generally isn’t centered around achieving the highest possible Mach number.

Instead, designers are asking:

• How far can it fly?
• How quickly can it accelerate?
• How effectively can it maneuver?
• How difficult is it to detect?
• How powerful are its sensors?
• How well can it resist electronic warfare?
• How effectively can it share information?
• How quickly can it employ its weapons?

Top speed is still useful.

It just isn’t the king anymore.

The New Definition of “Fast”

Modern air combat has essentially changed the meaning of speed.

Being physically fast is useful.

But getting information faster, making decisions faster and engaging the enemy faster can matter even more.

A fighter doesn’t necessarily need to be the fastest thing in the sky.

It needs to be the aircraft that gets the advantage before the opponent realizes the fight has started.

And that is why the modern fighter isn’t necessarily designed to win a race.

It’s designed to win the engagement.