John Butler and Jerry Kauphusman are 21st-century kamikaze pilots who come back to tell the tale every flight.

On Thursday morning that meant practically skimming over the ocean at 200 feet in a Learjet at 345 mph in the role of an anti-ship cruise missile. They can, and do, fly as low as 100 feet.

The little twin-engine jet, whose fuselage is so narrow passengers can touch both sides of the cabin with outstretched arms, buzzed the Pearl Harbor cruiser USS Chosin – one of its intended "targets" – and banked away for another pass.

The daily flights by a menagerie of civilian aircraft – including two 1960s Czech-built former military jets; two Hawker Hunters, a British-made fighter from the 1950s and 1960s; and three Learjets – are a unique aspect of Rim of the Pacific war games that the public rarely gets to see.

Kauphusman, a retired Navy helicopter pilot from San Diego who has been flying for the company Flight International for 14 years, said it’s hard for people to comprehend the type of flying he and other contracted pilots do during RIMPAC.

"You get, ‘OK, that sounds neat to do that.’ They don’t really know what it takes to fly low like this and execute the mission," he said.

The contracted civilian aircraft are part of a unique "Op For" (Opposing Force), fulfilling a role as enemy bombers and anti-ship cruise missiles.

The latter are of particular concern to the U.S. Navy fleet.

Russia has developed and sold the SS-N-27 Sizzler missile, which cruises low and slow and then develops supersonic speed, and China is developing anti-ship ballistic missiles.

U.S. Defense Secretary Robert Gates said in May that "other nations are working on asymmetric ways to thwart the reach and striking power of the U.S. battle fleet."

Iran is combining ballistic and cruise missiles, anti-ship missiles, mines and swarming speedboats as an offensive capability, Gates said.

"The virtual monopoly the U.S. has enjoyed with precision guided weapons is eroding – especially with long-range, accurate anti-ship cruise and ballistic missiles that can potentially strike from over the horizon," Gates said.

U.S. Navy ships defend against such a possible attack using the Aegis Combat System, which utilizes powerful radars and computers to track incoming threats and fire missiles in response.

For RIMPAC the Navy is using civilian aircraft from four mainland contractors: L3 Communications/Flight International, Phoenix Air, the Airborne Tactical Advantage Co. and Tactical Air Support.

The Navy was not able to provide the cost of the contracts late last week, but officials said the multiple flights made daily by the civilian aircraft flying out of the Marine Corps base at Kaneohe Bay come cheaper than using state-of-the-art fighters such as the F-18 Hornets that are on the aircraft carrier USS Ronald Reagan, which is participating in RIMPAC.

The civilian aircraft provide the "red" forces, while the U.S. is the "blue" force.

"If we can contract commercial air services out there to do that, it frees up the squadrons to perform their blue air (training) – which is what we really want them to do," said Navy Cmdr. Michael

Garvey, the Opposing Force air lead for RIMPAC.

The two Czech-built Aero Vodochody L-29 airplanes, one black and yellow and the other blue, white and gray, have top speeds of about 500 mph. U.S. Tomahawk cruise missiles fly at about 550 mph, the Navy said.

Flight International’s Learjets fly up to several times a day out of Kaneohe Bay on a mix of "profiles" either as an attacking bomber, an incoming cruise missile or a combination of the two.

"These airplanes are like old reliable trucks," Butler said of the Lears.

On Thursday’s "raidex," or raid exercise, Kauphusman was in the left seat of a 1983 Learjet 36 XR, which has big fuel "tip tanks" on the wingtips, and Butler was in the right seat.

The jet took off at about 10:15 a.m. accompanied by another Lear from Phoenix Air, looped around and then headed south over Oahu, and linked up with a light and dark gray striped Hawker Hunter about an hour later.

Kauphusman and Butler’s Lear was "Vader 1" (as in Darth Vader), the second Lear was "Vader 2" and the third aircraft was "Hunter One One."

The second Learjet carried a missilelike pod that sends out signals mimicking a missile or the radar of a specific aircraft – signatures that the ships below search for.

From an altitude of about 5,000 feet and

160 miles or more south of Waikiki, the Hunter dropped to low level and raced at the cruiser Chosin, which was about

30 miles away.

The British-made Hunter jet simulated a fast-running cruise missile as the two Lears came in from 10 miles behind. All three aircraft acted as a combination of incoming enemy aircraft and, at low altitude, inbound missiles.

At 200 feet and under an overcast sky, the Lear bounced along as ocean swells raced by.

The small white jet overflew the Chosin and then banked up to gain altitude for another pass on the cruiser’s "surface action group," which included about a half-dozen destroyers and cruisers from the U.S., Japan, Australia and other nations. Each ship was separated from others by several miles.

Butler and Kauphusman, the two pilots, repeatedly ascended and descended to buzz the ships. At the same time, they continuously coordinated their position and next plan with controllers.

As the Learjet swooped by at 345 mph, no one was visible on the ships, but there was plenty of activity.

Butler retired from the Navy in 2004 after flying F-18 Hornet and F-14 Tomcat fighters, and he said the realistic training provided in the simulated missile and bomber attacks is critical.

"They have a lot of simulations you can do," Butler said, "but you have to get out there and have your radar actually working and have everyone go through the process to the point of where you are simulating shooting a missile."