The White House is in a difficult spot when it comes to Syria. Not only is the United States at war with Islamic State, one of President Bashar al-Assad’s foes, but U.S. aircraft are also flying through the same airspace, and focused on part of the same mission, as the Syrian Air Force.

Even stranger, President Barack Obama came close to ordering airstrikes against Assad last year after a chemical attack in a Damascus suburb. Meanwhile, opponents in Congress want the president to go farther — either invading Syria outright or imposing a no-fly zone that would target the regime’s warplanes.

“I think that we would want to see an all-out war, shock and awe,” Representative John Fleming (R-La.) said. “We put troops on the ground, we put all of our assets there after properly prepping the battlefield, and in a matter of a few weeks we take these guys out … and we leave a stay-behind force to keep our friends up and going, and also maybe a no-fly zone in Syria over the area Assad controls.”

But neither the U.S. government nor Assad wants war with the other. The Assad regime isn’t thrilled that the United States and its allies are waging a bombing campaign inside Syrian territory — albeit in areas outside Damascus’ control. But it doesn’t want to lose what’s left of its air force trying to stop it. For the White House, clashing with the Syrian Air Force risks sucking the United States deeper into a horrendous civil war.

Still, the presence of the Syrian Air Force is a factor. The question is how much of a factor. If the Syrian Air Force were to challenge coalition aircraft, the United States would have to attack Syrian air bases, radars and surface-to-air missile sites that are still active and destroy them.

There’s also no doubt that Syrian jet fighters can pose an individual threat to U.S. aircraft. As waves of U.S. strike planes swept into Syria on Sept. 23, fighter pilots from Saudi Arabia, Bahrain, Jordan and the United Arab Emirates provided cover in case the U.S. jets were approached by enemy warplanes.

But three and a half years of heavy fighting have badly degraded Syria’s air force, rendering it incapable of putting up much resistance in the event of a clash with the United States and its allies. At least half of Syria’s airpower is gone, according to the Institute for the Study of War, due to a combination of enemy fire, rebels capturing air bases — mostly in northern Syria — and maintenance problems rendering planes inoperable.

What’s left is a mix of shoddy Soviet-era fighters, transport planes and helicopters. Yet the Syrian Air Force, maintained by a steady stream of Russian components, still plays a crucial role in the regime’s ability to continue fighting.

The bulk of Syria’s air combat power is concentrated in its fighter force. On paper, the Syrians have around 375 jets in the MiG-21, MiG-23, MiG-25 and MiG-29 versions. This number also includes Su-22 and Su-24 jets.

But that’s on paper. Few of these are capable of flying, and the air force has taken to cannibalizing some jets for parts so that others can fly. To put this in perspective, the largest single number of Syrian fighters are MiG-21s — at more than 100 planes — and these date back to the 1960s.

Syria is even more heavily dependent on its helicopters. It has several dozen Sa-342 Gazelle reconnaissance birds and several dozen Mi-24 Hind gunships. But its workhorses are roughly 100 — on paper — Mi-8 and Mi-17 transport choppers that fly daily missions to resupply its troops. The actual number, given wear and tear and combat losses, is likely a third of or half that.

The bulk of these planes and helicopters are based in three main air bases in and around Damascus. Three other bases in western Syria — Qusayr, Tiyas and Bassel Assad International Airport — are also in use. The regime has a handful of smaller bases, but these don’t see much use because ground crews and equipment are in short supply.

For these remaining planes, their missions include carrying out airstrikes, flying equipment from Russia and ferrying supplies around the country.

The Syrian Air Force has proven to be adaptable at these missions. Pilots learned to fly at higher altitudes to avoid rebel antiaircraft missiles and machine guns spread out in overlapping fields of fire. The Assad regime has dropped thousands of so-called “barrel bombs” — oil drums packed with explosive fertilizer that flight crews literally pick up and hurl out of helicopters. It’s a brutal and indiscriminate method of warfare.

Russia and Iran play a large role in keeping the Syrian Air Force in the fight. Moscow is Syria’s largest arms supplier and has been for years. The Kremlin provides everything, including jet fuel, bombs, small drones and spare aircraft parts. Shipments to the port of Latakia is the cheapest way to deliver supplies, but Russian and Syrian transport planes also fly in hardware.

Syria is dependent on Russian aid because its air force was never designed to fight this kind of conflict. Syrian air power was built around fixed-wing fighters, with the intent of fighting a short war with Israel. Using these fighters heavily in a ground-attack role for several years means components wear out fast.

Syria is also relying more on smaller aircraft like the L-39. This lightweight, agile jet is normally used for pilot training. In Syria, however, they’re armed with bombs and act as a deadly ground-attack plane because of their ability to loiter above a battlefield at slower speeds than fast-moving air-to-air dogfighters.

Russia is also bolstering Syria by delivering 36 Yak-130s, starting this year. These aircraft are similar to the L-39 except they are newer, even more agile and possess a longer range and greater armaments.

Beginning in 2016, Russia plans to deliver 12 MiG-29M/M2 fighter jets. These are some of the most advanced fighters that Moscow exports. They are designed for both air-to-air and air-to-ground combat. They’re also configured for dropping precision-guided bombs, which the Syrian Air Force lacks. Meanwhile, Syria has sent three Mi-24 gunships and 21 Su-24 fighters to Russia for refurbishing.

Russian advisers have flown surveillance missions in Syria using drones. But the bulk of Assad’s foreign advisers are members of the Iranian Quds Force, who are helping train loyalist militias.

There are also signs, however, that Iran is helping strengthen Syria’s air defenses. The Iranian military recently held a funeral for an officer with the 10th Air Defense Group, who died in Syria. This is an elite unit normally responsible for protecting Tehran’s ballistic-missile research complex in Iran’s Semnan province.

Syria’s antiaircraft missiles are crude but dangerous. The foreign?/Iranian? advisers are likely helping improve training and electronics, because Syria’s air-defense radars and tracking networks are poor and would not last long against a coordinated U.S. attack.

That is, if that scenario comes to pass.

But Syria has yet to do anything about the U.S. planes now roaring into its territory. During the first round of strikes, the Syrian military used only passive methods of tracking U.S. jets, according to Lieutenant General William Mayville, the Joint Chief’s operations director. This could mean listening to radio frequencies emitted by the planes, as opposed to actively tracking them — which involves bouncing radar signals off approaching aircraft.

The Syrians likely used passive instead of the more-accurate active tracking because U.S. pilots could detect the latter’s pings and interpret it as a threat. That might provoke the pilots to shoot back, and overnight, the one advantage the regime has over the rebels would vanish.

Neither the United States or Syria wants that — for very different reasons.

PHOTO (TOP): Syrian air force L-39 Albatros launches rockets near the Turkish-Syrian border, Jan. 5, 2013. Syrian Air Force photo

PHOTO (INSERT 1): Russian Su-24 fighter-bombers during a June 28, 2003 exercise. Igor Zarembo/Presidential Press and Information Office photo

PHOTO (INSERT 2): The Syrian Air Force relies heavily on Mi-17s and Mi-24s, similar to these Afghan helicopters, for both ground attack and resupply missions, April 28, 2010. WIKIPEDIA/Commons, David Quillen/U.S. Navy photo

PHOTO (INSERT 3): Syrian MiG fighters at an undisclosed location, September 2013. Syrian Air Force photo

PHOTO (INSERT 4): Aero L-39 Albatros planes of the Breitling Jet Team from France take part in an aerobatics display at the Malta International Air Show at Malta International Airport outside Valletta, September 26, 2009.

REUTERS/Darrin Zammit Lup