The North Korean air force is short of fuel and many of its planes are decades old, no match for the modern firepower of the U.S. military. But the fighter jets that intercepted a U.S. reconnaissance plane are the North's best combat planes, and could easily have shot down the unarmed craft.
The incident off North Korea's east coast Sunday highlighted the role of the communist air force in the standoff over its efforts to develop nuclear weapons. Analysts believe the North is staging provocative acts to push the United States into talks on a nonaggression treaty and economic handouts.
Debate about the military threat from North Korea usually focuses on its huge conventional ground force, its chemical arms, its large stock of missiles and possibly one or two nuclear weapons. The air force has as many as 1,600 planes, but most are based on old Russian and Chinese designs from the 1950s and 1960s. North Korea does not manufacture airplanes.
"They have a lot of stuff that should be in military museums," said Patrick Garrett, an analyst at GlobalSecurity.org, an Alexandria, Va.-based research center on security issues.
A lack of fuel allows North Korean pilots only a fraction of the flying time enjoyed by South Korean military pilots and American air crews deployed in the South. It's possible, however, that the North Koreans are conducting simulator work on the ground to compensate for little experience in the air.
Larry Wortzel, a former military attache at the U.S. Embassy in Beijing, said he believed the North Korean air force and the rest of the military rely heavily on fuel from China, a traditional ally.
"The Chinese are really helping them out," said Wortzel, now head of Asian studies at the Heritage Foundation, a research center in Washington.
Two of the four North Korean fighters that intercepted the U.S. Air Force RC-135S reconnaissance plane were MiG-29s, the best of the North's estimated 600 combat aircraft and roughly equivalent to the American F-16 fighter in capability.
"They were probably tickled to death to be out on this mission because it gave them significant flying time," said Bruce Bennett, an analyst at the Santa Monica, Calif.-based Rand Corporation.
The North Korean fighters illuminated the U.S. plane with targeting radar, but there was no hostile fire, the Pentagon said. The U.S. plane broke off its mission and returned to its base in Japan.
Bennett described the MiG-29 as the "flagship" of the North Korean air force, which has about 20 of the Soviet-made planes, a fraction of the 150 F-16s owned by South Korea. The North upgraded its air power in the 1980s with Soviet help, but much of its equipment is virtually obsolete.
Jets such as the MiG-21 and MiG-23 form the backbone of the North Korean air force. On Feb. 20, a North Korean MiG-19 warplane crossed over the South's western sea border, but quickly retreated after South Korean jets flew to the area. It was the first such intrusion since 1983.
Also in 1983, a North Korean pilot defected by flying his MiG-19 across the border into South Korea. Another pilot did the same in 1996, arriving in a helmet that was at least 30 years old and wearing cotton cloth in place of socks. The dismal state of the elite officer's equipment was a sign of the North's economic difficulties.
Wortzel said that while North Korean pilots are capable of interceptions and firing missiles, they would not fare well in aerial combat with American planes. They would also have trouble dodging missiles that lock onto their craft, he said.
North Korea also has Soviet-made, An-2 transport planes that could fly low to avoid radar and insert special operations forces into South Korea, according to Southern intelligence reports.
The head of the air force is 56-year-old Oh Kum Chul, a three-star general, according to South Korea's Unification Ministry.
North Korean air bases are concentrated around Pyongyang for defense of the capital, and near the heavily militarized border with South Korea, just minutes of flying time from the South Korean capital of Seoul.
North Korea is believed to have many underground shelters for its aircraft, and could use paved highways as airstrips and park planes under overpasses in the event of war.
Air defense systems are plentiful, if rudimentary. Communist military planners probably recall the fate of their air force in the 1950-53 Korean War, when U.S. combat aircraft quickly dominated the skies and bombers pounded North Korean cities and military installations.