The aircraft Kim Jong-un fears most. Or ought to.

America’s newest fighter-bomber, the F-35, is coming to Asia in increasing numbers just as tensions between North Korea and the United States have escalated. This should worry Kim Jong-un.

“We’ve passed more than 100,000 flying hours (many with test pilots, to be sure), and they are ready to go into combat,” Heather Wilson, the US Secretary of the air force, said in an end of August briefing.

Already one squadron is now stationed in Japan. Dozens more are coming to US and allied bases in Japan and South Korea.

The first squadron of 16 planes arrived at Japan’s Iwakuni Marine Corp Station in January. They took part in the Foal Eagle military exercise in South Korea that just ended, where they made bombing runs on simulated North Korean missile bases.

Kim Jong-un is clearly spooked by the American B-1 long-range bombers stationed on Guam. They fly show-of-force missions along the Korean DMZ, as they did this week after North Korea fired a missile over Japan and threatened to lob four missiles into waters off Guam.

But Kim may have more to worry about from flights of F-35 fighter-bombers from bases in South Korea and Japan if a military conflict breaks out on the Korean Peninsular.

The F-35 “Lightning” is the most advanced fighter in the American inventory. It comes in three models, The F-35A, which is the air force version; the F-35B for the marines and F-35C naval version. The Marine version is capable of vertical takeoff and landing (VTOL).

The F-35 can reach speeds of up to Mach 1.6, or nearly twice the speed of sound. It’s stealth design and coating of radar absorbents make it practically invisible. It is the first so-called “Fifth Generation” stealth fighter in the region.

According to Aviation Week, the three air forces facing North Korea will have about 100 of the fighters by 2020, deployed in a kind of arc from South Korea’s Kunsan air base to Japan’s Misawa air base in northern Honshu.

On paper it would seem that the F-35 could easily brush aside North Korea’s comparatively ancient air defenses in any sustained attack on North Korea. The North’s most capable fighters are a handful of Sukoi-15 and MiG-29s, both of late Cold War vintage.

South Korea has purchased 40 of the planes arriving by the end of next year. Japan has bought 42 that are now rolling off the Lockheed Martin assembly lines in Texas. The first four were built there, but the remaining 38 will be assembled by Mitsubishi Heavy Industries in Japan.

Acquisition of the F-35 will give the Japanese military something that it has always lacked – namely a capability to strike back at North Korean bases if they launch a missile at Japan or even to strike pre-emptively.

Acquisition of the F-35 will give the Japanese military something that it has always lacked – namely a capability to strike back at North Korean bases if they launch a missile at Japan or even to strike pre-emptively.

Such a scenario became even more plausible after North Korea launched an intermediate range missile that flew over Hokkaido this week.

Defense Minister Itsunori Onodera said Tokyo did not consider trying to shoot the missile down as it was not likely to land on Japan proper.

Onodera has argued that the constitution as presently interpreted would allow Japan to attack a base firing missiles at Japan, but it has lacked the means to do so. That may be changing.

The VTOL version has an added capability of being launched from warships. The assault ship USS Wasp has been reconfigured to launch and retrieve the F-35B. It is based at the Sasebo base in Japan as headquarters for the Marine expeditionary force.

America’s newest warship, named appropriately the USS America, is designed to carry a full complement of F-35Bs.

It is based in San Diego, but has been sailing in the South China Sea lately (indeed it was a first responder to the recent collision between a tanker and the USS John McCain).

One question is whether the Japanese “helicopter destroyers” such as the Izumo and its sister ship the Kaga could be converted into mini aircraft carriers capable of launching F-35 strikes.

It would require considerable refitting. For example, the flight deck would have to be coated with a fire resistant substance, otherwise the plane would burn a hole in the deck on take off.

At the moment, Japan does not possess any fighters capable of vertical launches and there is no indication that it wants any. The only VTOL in the Japanese inventory is the controversial Osprey a marine transport plane.