Competition in the jet fighter market is heating up. Russia and China are proposing partnerships on advanced fighters while the United States is propelling its $30 million Joint Strike Fighter into the market by 2011.

But there's a military buildup that the industry, indeed many governments, seem to be ignoring: the technical evolution of surface-to-air missiles, which will soon outstrip the capabilities of the aircraft. Like the battleships of the 1920s, manned combat aircraft are on the cusp of obsolescence, awaiting only their Pearl Harbor to reveal this reality.

As countries devote resources to acquire aircraft already struggling to survive over the modern battlefield, they risk defeat by foes that embrace and innovate the next generation of weapons systems. The elimination of manned combat aircraft from the battlefield will force a complete overhaul in military doctrine. If the obsolescence is demonstrated suddenly, the course of a conflict could shift dramatically.

The fighter, with the primary mission of destroying other fighters, is a parasitic weapon system, and many now incorporate bombing capabilities to boost cost-effectiveness. Still, until air defense improved beyond anti-aircraft artillery for destroying bombers and reconnaissance aircraft -- or until the bombers and reconnaissance aircraft were replaced -- the fighter remained necessary.

Both events have transpired.

New systems rival the manned aircraft in bombing and reconnaissance roles. Meanwhile, advances in surface-to-air missile (SAM) systems have forced the development of costly and complex countermeasures and have pushed aircraft maneuverability beyond the physical capacity of pilots.

Cruise missiles and theater ballistic missiles proliferate widely and already challenge the aircraft's bombardment role. When the United States launched a punitive attack on Libya in 1986, it used F-111 bombers. When Washington launched retaliatory strikes against Baghdad in 1996 and against alleged assets and allies of Osama bin Laden in 1998, it used cruise missiles. The United States used ship- and submarine-launched BGM-109 Tomahawk cruise missiles and air-launched AGM-86C cruise missiles against Iraq during Operation Desert Storm and against Yugoslavia during Operation Allied Force, particularly for targets deemed too well-defended to risk manned aircraft.

The United States is not alone in developing and deploying cruise missiles, though it is the only country since Germany and its V-1 to use them extensively in battle. Current models are expensive and relatively simple, though work is under way to improve effectiveness and reduce cost.

One example is LOCAAS, the low-cost autonomous attack system under development in the United States. This system is designed to identify and prioritize a variety of targets and to configure its warhead for maximum effectiveness against the chosen target -- all for less than $100,000, compared to the $600,000 to $800,000 Tomahawk.

Also, some 16 countries deploy theater ballistic missiles such as the Scud and its variants. At about $350,000 to $500,000 per missile, these are cheap alternatives to strike aircraft, especially against well-defended targets. Like cruise missiles, ballistic missiles are still rather simple, and their effectiveness is likely to increase as they are modified to defeat countermeasures.

These are just the systems currently deployed. Space-based weapons platforms, hypersonic intercontinental weapons systems and unmanned combat vehicles are all on the drawing boards or exist as developmental prototypes.

In the reconnaissance role, unmanned aerial vehicles (UAVs) augment already well-established satellites. Still in their infancy, UAVs were used extensively for tactical reconnaissance over Kosovo during Operation Allied Force. Portable UAVs that look like model airplanes small enough to fit in a soldier's backpack are under development.

Although cruise missiles and UAVs do not necessarily sound the death knell for manned combat aircraft, SAMs do.

SAM systems have already succeeded in dramatically reducing the cost effectiveness of manned aircraft operations. As long ago as 1972, North Vietnamese air defenses forced the United States to send 42 support aircraft for every package of 16 strike aircraft.

Of these, 22 were needed just to counter the crude SAMs of 30 years ago. These additional aircraft included chaff dispensers and electronic jammers to confuse SAM radars, their escorts and "Wild Weasels," which seek out and destroy the radars of SAM systems.

Evolution of SAM systems has driven the evolution of countermeasures. Modern combat aircraft carry chaff and jamming pods to confuse radar and flares to confuse infrared seekers. Dedicated air-defense suppression aircraft, the Wild Weasels, also support them. The newest combat aircraft have turned to stealth technology in hopes of eluding SAMs. To date, these measures have worked, though largely due to stagnation in SAM tactics.

The final, insurmountable weakness in manned combat aircraft is the pilot's own physiology. Maneuverability is the last line of defense for combat aircraft. Consider the fact that a 30-year-old design like the F-16 is capable of sustaining nine g's, or nine times the force of gravity. At this level, pilots black out. Now consider the Russian-built SA-10. It's capable of traveling at six times the speed of sound and maneuvering at 100 g's. The F-16 looks like a snail by comparison.

SAMs are nearly ubiquitous. At least 120 countries possess SAM systems, ranging from the simple and outdated Russian SA-7 shoulder-fired missile to the advanced SA-10 - also known as the S-300 - which has attracted Western buyers. At least 25 countries build SAM systems or components, and others are developing their own systems. Iran, for example, tested an indigenously developed SAM in April 1999.

Manned combat aircraft, at a tactical level, are currently the measure of national power. They are tools of force projection -- and when able to seize air superiority, aircraft can sway the battle on the ground. But they stand today at the brink of obsolescence: Missiles already vie for the bombardment role, and satellites and UAVs perform reconnaissance duties. Only transport aircraft lack a ready substitute. Finally, the tactics and technology of SAMs are on the verge of overcoming aircraft defensive countermeasures.

There will certainly be a role in the future for manned combat aircraft. Not everyone can afford a satellite, and cruise missiles are not effective in a gunboat diplomacy role. Troop transports still need escorts, and there may be missions too politically sensitive for unmanned weapons. But the manned combat aircraft's role as the cornerstone of modern military strategy is ending.

In 1922, the great powers focused on battleships as the measure of national power, even as the precursor of the battleships' doom, the aircraft carrier USS Langley, was christened.
Though Billy Mitchell's warning that battleships were vulnerable to aerial attack was ignored, the bombing of Pearl Harbor ultimately demonstrated the ascendance of the aircraft carrier and launched a revolution in naval strategy. As countries continue to pour resources into manned combat aircraft, they risk a similar rude awakening.

Matthew Baker is a senior analyst at STRATFOR, the global intelligence company. For more information about STRATFOR, click here.