Brand-new L-159 bomber jets take off most days from this expansive facility, climbing fast into the skies for training missions. Replacements for retired Russian-made Su-22s, the locally built jets carry advanced Italian-made radar systems that allow for strikes in complete darkness.

These light combat aircraft are efficient and modern, but of the 38 planes on order, only 27 have been delivered, not enough for all of the pilots at this base. The deputy base commander estimates it will be two years before the first pilots will be ready for combat operations with their NATO allies.

Once a source of national pride, the Czech air force has fallen on hard times, highlighting the costs and difficulties of transforming the military of a former communist state into a reliable and battle-ready partner in NATO, which added the Czech Republic as a member in 1999.

At another military base, other units of the Czech military are turning the past into an asset for the future. At the 9th NBC Company barracks in Liberec, soldiers in self-cooling protective gear practice responding to a simulated chemical attack, using skills acquired during the Cold War, when Czech troops were the Warsaw Pact's specialists in defense against nuclear, biological and chemical attack.

Within an hour, a small unit can extract 60 injured people from a "hot zone," provide medical care and decontaminate the area -- in scorching desert temperatures of over 120 degrees, officials said. It's an expertise the Czechs recently demonstrated to U.S. forces training in Kuwait, as part of Operation Enduring Freedom. "I think we surprised a lot of people in Kuwait," boasted Maj. Jiri Gajdos, the company commander, who had recently returned from the desert exercises.

Soldiers involved in the nuclear, biological and chemical unit joke that NBC once stood for "No Body Cares." But when the leaders of the 19 NATO countries gather later this month in Prague, the Czech Republic's capital, the Czech military's NBC defensive capabilities, not its struggling air force, will be the focus of a display for the media and the assembled leaders.

Czech officers, defense planning officials and diplomats said the Czech example offers lessons to the seven East European countries that, during the summit, will be formally invited to join NATO. Like the Czech Republic, they are former communist states, most with small populations and struggling with limited budgets to replace and upgrade Soviet-era equipment and inefficient military command structures.

As part of their contribution to NATO's military might, countries can compensate for a lack of manpower and high-tech weaponry by adopting specialized "niche" expertise, military officers will tell them in Prague. "I believe after three and a half years [in NATO], we are finding our position as a small country which is able to contribute something meaningful," said Jan Vana, director general of the Czech defense department's strategic planning division. "This is something [the new members] may want to consider."

The old NATO was about countries with large standing armies, each with similar capabilities, poised to defend against a Soviet invasion from the east, George Robertson, NATO's secretary general, said in an interview.

"The new NATO," he said, "is going to be about countries who do different things, and do each of them well."

The army of Romania, a country that is likely to be invited to join, has units long renowned for their mountain-fighting skills. The three Baltic states, Latvia, Lithuania and Estonia, also set for membership, might contribute police units for peacekeeping and police-training missions.

The Czech Republic and the two other countries that joined in 1999, Poland and Hungary, have had varied success in restructuring their armed forces to fit into the alliance. Poland, the most populous of the three, and with much greater resources and a long-term military modernization program, has gone furthest, military analysts said. Hungary, with the lowest rate of defense spending as a percentage of gross domestic product, and a lack of political commitment to the military in previous governments, has done the least.

Somewhere in-between is the Czech Republic.

"The totally old dinosaurs are gone" from the ranks, said Ivan Dvorak, the Czech deputy director of strategic planning. But some problems persist. "We have a lot of ammunition and stocks we do not need. We have excessive infrastructure we do not need. The personnel structure has to be changed."

The three new members joined NATO less than two weeks before the start of the alliance's bombing campaign against Yugoslavia, a high-tech operation for which the three found themselves largely unprepared. Michael Zantovsky, who chairs the foreign affairs, defense and security committee in the Czech Senate, said that every new country "always thinks they are ready, and they are wrong, including us."

But the Czech Republic got a political dividend, he said. "The idea was that joining NATO would help with the self-identification of the nation as a Western, democratic nation bound by the same rules, and it may have helped accelerate democratic transformation" in the three new members.

But what followed, he said, was "a steep learning curve, for the brass and everyone else involved."

One of the biggest immediate problems facing the Czech Republic when it joined was that too few of the country's soldiers spoke English well enough to allow for smooth joint operations with NATO. "That was not a success story," said Dvorak. "A great number of people had been studying in academies abroad. But the military lost these people because the [military] career system didn't work."

English remains a problem. "We are successfully getting over the language problem, but we are not where we should be," said Gen. Martin Herja, a pilot and deputy commander here at the 32nd Tactical Air Base.

Obsolete equipment, mostly vintage stock from the Soviet-dominated Warsaw Pact, proved a greater obstacle than did the language barrier.

The Czech air force fleet of MiG-21 fighters will reach the end of their operational lives in three years, and some of the jets are already grounded for lack of spare parts. Over the last 10 years, 20 pilots have been killed in accidents blamed on poor training, and reduced flight hours have prompted many pilots to quit.

When the last of the MiGs are retired from service, the air force will be left without a single supersonic fighter. That's because the need for funds to clean up after disastrous flooding in August forced the government to divert about $2 billion that was set aside to buy new Swedish- and British-made Gripen combat aircraft.

As the old Russian jets are retired, the Czech Republic can slowly wean itself away from Moscow's spare parts pipeline. Many here would be happy to end that relationship, continuing to feel deep distrust of Russia 13 years after the Velvet Revolution peacefully deposed the Moscow-backed Communist government of Czechoslovakia, now two countries, the Czech Republic and Slovakia.

"We need aircraft made in the Czech Republic, or in the West," said Herja, the pilot, "in order to be independent."

The size of the armed forces also remains a problem -- there are more than 60,000 members, and planning officials said the target number is close to 36,000. The government is phasing out the draft, but the army will not be fully made up of volunteers as required by NATO until the end of 2006, the officials said.

The use of conscripts creates an added problem. Under the Czech constitution, draftees cannot be deployed outside the country's borders, meaning that at present half the armed forces could not be used for foreign NATO operations.

A trimmed-down military force would also have to recast a top-heavy command structure. The number of garrisons, now at 140, will be reduced to 50. "Our armed forces are so small, we don't need so many levels of command," said Dvorak.

Another shortfall is the military's lack of transport planes for moving soldiers and equipment long distances. Czech troops currently train in Kuwait and operate a medical facility in Afghanistan. But to get there, the soldiers in Afghanistan resorted to commercial aircraft.

The Prague government is currently in talks with Moscow about converting part of the debt Russia owes the republic into three Antonov-70 cargo planes.

Dvorak said their goal is to develop within four years the capability to dispatch a 5,000-man brigade for six-month deployments -- "something that would be totally unimaginable today," he said.

Gen. Martin Herja displays one of the new Czech L-159 light attack jets that are replacing the country's aging Soviet-era fleet. "We need aircraft made in the Czech Republic, or in the West, in order to be independent," he said.