Speed is no longer the absolute criterion for fighter jets. But it still plays a strategic role in the face of stealth technology and modern sensors.
In summary
Speed has long been synonymous with fighter jet superiority. Today, it is no longer the ultimate criterion, as modern surface-to-air missiles far exceed the performance of even the fastest fighter jets. However, speed remains a key parameter in certain scenarios: penetrating hostile airspace, surviving missile fire, or rapid repositioning. The physiological limits of pilots, who cannot sustain more than 9 G for long periods, require a new approach to the design of future fighter jets. Stealth, on-board AI, data fusion, and passive sensors are profoundly changing the way air superiority is conceived. Future programs—NGAD, Tempest, GCAP, and SCAF—now combine sustained speed, low signature, and software autonomy. This article examines why speed is no longer everything, but remains a strategic variable, and seeks to understand which technological direction is most consistent for the fighter jets of tomorrow.
The evolution of speed in the history of fighter aircraft
The race for speed has shaped military aviation for more than fifty years. The first supersonic fighters of the 1950s, such as the F-100 Super Sabre, had the sole objective of breaking the sound barrier in horizontal flight. Models in the following decades pushed the limits even further. The MiG-25 Foxbat reached Mach 3.2 (≈ 3,920 km/h) in high-altitude interception, while the SR-71 Blackbird regularly maintained Mach 3 (≈ 3,530 km/h) on strategic reconnaissance missions.
These extreme performances shaped an era when “going faster than the threat” seemed the most rational approach. Ground-to-air defenses were less automated at the time and their reaction times were slower. Speed offered a margin of safety.
This logic collapsed with the advent of modern surface-to-air missiles. The S-300, S-400, and Patriot PAC-3 systems intercept targets traveling at several thousand kilometers per hour and maneuvering abruptly. A fighter jet traveling at Mach 2 no longer has any guarantee of survival against these defenses. Speed is no longer the absolute answer.
Speed as a factor in survival reduced by new defenses
Today, AESA radars can detect a target several hundred kilometers away, even if it is flying very fast. Modern missiles reach Mach 4 to Mach 6 (≈ 4,900 to 7,350 km/h), and even more for some hypersonic weapons. No piloted aircraft can maintain such acceleration.
The current doctrine is based on three main principles:
– reducing radar signature to avoid detection;
– saturating the adversary with advanced sensors;
– maneuvering intelligently rather than relying on raw speed.
Pilots know that it is impossible to physically “escape” a modern missile solely by speed. Evasion maneuvers rely primarily on:
– energy breaks, which use maneuverability rather than speed;
– electronic warfare systems;
– infrared decoys;
– radar lock break.
Speed still contributes to these techniques, but no longer dominates the strategy for using modern fighter jets.
Human limitations: a major obstacle to ultra-fast aircraft
Even if an aircraft could reach Mach 4 in sustained flight, its pilot would not be able to complete the mission. The human body has difficulty tolerating prolonged accelerations exceeding 9 G with modern anti-G suits. At these levels, vision deteriorates and the risk of loss of consciousness is high.
The example of the F-22 Raptor, capable of supercruise at Mach 1.8, is revealing. Although the aircraft can exceed Mach 2, its real strength lies in its ability to maintain supersonic speed without afterburners and to maneuver under heavy load. Extreme speed is no longer an end in itself, as it would quickly put the pilot in danger.
Future programs, such as the US NGAD, plan to integrate escort drones capable of exceeding human limits. These aircraft will be able to perform turns at 15 G or 20 G without physiological constraints. Their presence will profoundly transform the use of speed.
The stealth era: when discretion is worth more than Mach 3
Since the 1990s, “invisible” performance has often counted for more than speed. The F-117 Nighthawk, incapable of exceeding Mach 1, penetrated some of the world’s most protected airspace thanks to its very low radar signature. The F-35 follows the same logic: moderate speed but stealth, data fusion, and versatility.
This approach is based on a clear principle: not being detected is more useful than trying to escape after being detected.
New fighters therefore favor:
– wave-absorbing geometric shapes;
– RAM coatings;
– passive sensors, such as the F-35’s DAS;
– LPI (Low Probability of Intercept) modes.
In this context, speed becomes secondary. Excessive speed would increase the infrared signature, and therefore vulnerability. Stealth requires compromise.
AI and new sensors: toward information superiority rather than speed
Air warfare is now played out in the information bubble of fighter jets. Speed is only useful if it is part of a coherent tactical whole.
The armed forces are therefore focusing on:
– multi-sensor data fusion;
– on-board AI to analyze threats;
– secure and discreet communications;
– long-range electro-optical and infrared sensors.
The F-35 illustrates this trend: it is not the fastest, but its sensor system can detect an aircraft more than 150 km away in passive mode, without emitting a signal.
Future SCAFs, GCAPs, and NGADs go even further with the integration of:
– AI-controlled drones;
– cloud architectures in combat;
– sensors distributed across multiple platforms;
– connected missiles.
Speed remains a tactical parameter, but the decisive advantage lies in information prior to engagement.
The question of hypersonic aircraft: an attractive but impractical option
The idea of a piloted hypersonic aircraft capable of exceeding Mach 5 (≈ 6,125 km/h) regularly comes up in discussions. Its potential is appealing: penetrating airspace very quickly, striking, and then leaving before any interception.
In reality, however, there are several obstacles:
– temperatures exceed 1,000°C at these speeds;
– structural materials melt;
– the pilot would not survive the acceleration;
– control systems would be unstable;
– the infrared signature would be enormous.
American programs such as HTV-2 have shown that hypersonic aerodynamic stability is extremely difficult to control. Manufacturers are therefore focusing on autonomous hypersonic missiles rather than piloted aircraft.
The hypersonic field will remain relevant for weapons, but is unlikely to be used for manned fighter jets for several decades.
The desired balance: sufficient speed, high stealth, and electronic brains
The future of fighter jets is no longer decided on the basis of a single criterion. Current programs favor a coherent combination:
– sustained speed greater than Mach 1.5 in supercruise;
– very low radar signature;
– sufficient maneuverability to evade a missile;
– Onboard AI to manage sensors;
– Cooperation with accompanying drones;
– Computing power to manage data fusion.
The NGAD should reach a maximum speed greater than that of the F-22, but without sacrificing stealth or software autonomy. The European SCAF is moving in the same direction by combining manned aircraft, swarms of drones, and open architecture.
Speed is therefore becoming a complementary asset, not a central objective. It is used to penetrate, strike, extract, or reposition. But it no longer has the absolute strategic value it had during the Cold War.
A future where speed becomes useful again, but never alone
The fighter jets of tomorrow will fly fast, but not too fast. They will be stealthy, but never invisible. They will incorporate AI, but the pilot will remain the decision-maker. Speed will continue to play a key role in several situations, particularly for evading missiles or exploiting a window of opportunity to fire. But air superiority will rely primarily on information, connectivity, and discretion.
Speed remains a weapon, but it is no longer the primary one that engineers seek to hone. The next generation of air combat will be a blend of energy efficiency, advanced stealth, smart sensors, and sufficient speed to shape the battlefield. The real revolution will not come from record Mach speeds, but from the way aircraft understand, share, and exploit information.
Sources
– USAF technical reports on the performance of modern fighters
– Publications on NGAD, Tempest, and SCAF
– Analyses of modern surface-to-air systems
– Public data on fighter aircraft speeds and capabilities
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