But we long ago reached a point of diminishing returns. Both the 50s-60s B-58 Hustler and the old Vietnam-era F-4 Phantom still hold speed records, and they are way obsolete. Even our Blackbirds, the fastest planes ever built, are now obsolete and decommissioned. Even the Aurora, which was supposed to be its replacement, was just a cover story for the subsonic Stealth program.

We already have missiles and munitions that can go very fast, and our jet fighters today aren't that much faster than they were during the 60s. Other missions, such as close recon, attack, ground support, tank busting, etc cannot use high speeds. Modern warfare relies more on avionics, sensors, stealth, navigation, communication, countermeasures, VTOL and so on. Other factors are also critical, such as loiter time, range, maneuverability, coordination with other units (both air and surface), ordnance loads, targeting capability, etc. I simply don't see a reason for aircraft to go that fast. Missiles, yes, but we already have that. Our fastest high-flying fighters and bombers are now vulnerable to missiles and radar, so we now rely more on terrain-hugging and stealth technology to avoid detection and interdiction. A lot of our frontline aircraft are now subsonic. Air-to air combat occurs at subsonic speeds, you only need high speeds to catch your enemy, or to escape from him.

Something very similar happened with ships. Destroyers, cruisers and battleships could easily exceed 30 knots in the WWII era, to outmaneuver their opponents in fleet actions, but it soon became apparent that you couldn't outrun an airplane, missile or a homing torpedo, and ship's weapons and fire control made elaborate maneuver ballets as obsolete as tacking duels.

There is no fancy footwork involved, essentially, the first guy who sees his opponent and throws a punch wins. Modern warships are actually slower than the same classes of combatants 60 years ago. The only exceptions are submarines and aircraft carriers, but for totally different reasons than you might expect.

Submarines need to go fast to evade destroyers and their ASW sensor systems. Aircraft carriers need to go fast to create a flight deck-relative wind which will allow them to launch heavier-laden aircraft, not for maneuver and evasion.

Don't get me wrong, there is no doubt more speed is always better, but we may be paying too high a price for it. But of course, the Flag Rank officers and engineers love their fast and expensive toys and elaborate high-tech weapon systems. Successfully managing big programs is how you advance your career once you reach the rank of Admiral or General, not to mention all the networking you get to do with the heavyweights in Congress and the Defense Biz.