ABU AD DUHUR, Syria — The rebels huddled before darkness near the edge of the Syrian air force base. They were about 40 men, hiding beside small buildings on the flatlands south of Aleppo.


Each man carried little more than a rifle and several dozen cartridges. They had gathered for an effort that illustrated the lopsided nature of the fight for Syria: lightly armed men trying to remove Syria’s attack jets from the skies.


Roughly two months into this important yet scarcely documented battle, Syria’s antigovernment fighters have succeeded in laying siege to the heavily fortified Abu ad Duhur air base. They have downed at least two of the base’s MIG attack jets. And this month they have realized results few would have thought possible. Having seized ground near the base’s western edge, from where they can fire onto two runways, they have forced the Syrian air force to cease flights to and from this place.


“We are facing aircraft and shooting down aircraft with captured weapons,” said Jamal Marouf, a commander credited by the fighters with downing the first MIG-21 here. “With these weapons we are preventing aircraft from landing or taking off.”


This is a significant setback for the government in the northern region, where rebels had already strengthened their position with homemade bombs, making roads too perilous for military vehicles to pass and restricting the military’s movements.


But air power has remained a large advantage for President Bashar al-Assad, whose air force has pounded many cities and towns.


For the rebels, managing to deny the use of this airfield has undermined the government’s ability to exert its full authority in some parts of the country. It has also improved the morale of fighters who remain severely outgunned.


The rebels’ boldness, and their success, have not been painless. The army units inside the base have tanks, artillery and mortars. When attacked, the soldiers often respond by firing barrages of high-explosive rounds into the nearby town, in what amounts to a tactic of collective punishment against civilians. The effects are evident in the center of town, where block after block of buildings have been shattered. “This is the army, taking revenge,” said another fighter, Abu Razaq.


The events at Abu ad Duhur form another telling chapter of the uprising’s evolution, and for the tit-for-tat fight between the government and its adversaries.


The crackdown by the Assad government has descended in stages since it started last year. It began with arrests but quickly shifted into a bloody campaign by loyalist militias and a conventional army using mortars, artillery and tanks. This summer, as the campaign slowed in the face of swelling rebel ranks and roadside bombs, the government escalated again. It turned loose helicopters and then jets to attack rebels and their neighborhoods.


After the government moved its battle to the sky, at least hundreds of fighters from the mountains diverted some of their attention from the remaining army outposts near their homes and began infiltrating into the lowlands. Armed with a paltry assortment of weapons, they began hunting the aircraft that were hunting them.


Mr. Marouf, 37, is from Deir Sonbul, a village in Jebel al Zawiya, an area of rolling mountains where mosques and Muslim cemeteries stand beside Roman ruins and where olive groves cloak the slopes. Before the war he had been a construction contractor in Lebanon.


Now he is one of the rebels’ most prominent field commanders, his stature elevated in part by YouTube videos in which he is seen striding among the flaming wreckage of MIGs to stand over the bloodied remains of Syrian pilots still strapped to their parachutes. In one video he declared that if the world would not protect Syrians by enforcing a no-fly zone, then the rebels would create a no-fly zone themselves. That statement was fired in part by adrenaline, made moments after knocking a Russian-made jet from the sky.


In an interview after last Friday’s prayers, Mr. Marouf offered a more measured view and an assessment heard throughout the rebel-held zones. The Syrian opposition, he said, needs antitank weapons and shoulder-fired antiaircraft missiles, which would help the rebels defeat the government’s armor and ground its planes. Then he again offered a confident declaration.


“If they send us these, we will destroy this regime in less than 30 days,” he said.