This undated photo released by aerospace technology company Northrop Grumman shows the Global Hawk unmanned aircraft. (AP Photo/Courtesy of Northrup Grumman)

With U.S. airstrikes in Iraq continuing, President Obama has authorized surveillance flights into Syria in an effort to gather intelligence on Islamic State forces.

The move marks an escalation against the radical Islamist group, and some observers have suggested that the flights are a precursor to airstrikes like those being carried out across the border in northern Iraq. But sending surveillance flights into Syria would be complicated and potentially dangerous for both manned and unmanned aircraft.

As our colleague Greg Miller noted over the weekend, any U.S. aircraft in Syria could be seen by the government of President Bashar al-Assad as a threat, in part because they could gather valuable intelligence on his forces. Syria’s foreign minister, Walid al-Moualem, has already signaled that Damascus would not tolerate unilateral U.S. strikes against the extremists.

Drones such as Predators, Reapers and even the high-flying Global Hawk could be easily shot down by both the Syrian air force and the country’s air defense grid, according to a former drone operator.

While the U.S. military has penetrated Syrian airspace on at least one occasion over the past year — during the failed bid to rescue journalist James Foley and other Americans being held by the Islamic State — that raid involved the use of modified Black Hawk helicopters. The helicopters are designed to fly into hostile air space and conceivably could have been flown at very low altitudes to avoid radar detection.

Surveillance aircraft, however, operate high and slow.

“These aircraft are not built to go into denied airspace,” the pilot said, who requested anonymity due to the sensitivity surrounding his former employment. “If the Syrians wanted to send up a MiG 23 and shoot down a Predator, they could easily do it.”

In addition to fielding a moderately capable air force, Syria possesses advanced surface-to-air missile systems like the SA-22 Greyhound, according to Military Balance, a publication issued by the International Institute of Strategic Studies that documents foreign military capabilities.

The SA-22 can hit targets up to 65,000 feet, which coincidentally is believed to be the maximum altitude of the Global Hawk.

Other high-flying U.S. military assets include the RQ-180, a stealth drone that could avoid radar-guided surface-to-air systems, and the U2 spy plane, which flies well above 70,000 feet. But those aircraft are usually used to monitor larger targets and could have a difficult time tracking small groups of militants, particularly if they are intermingled with the civilian population.

That doesn’t mean U.S. forces aren’t trying. The former pilot speculated that any U.S. aircraft that successfully made it into Syrian would be given a number of tasks to gather intelligence about the Islamic State, sometimes referred to as the Islamic State of Iraq and Syria.

The former pilot noted that surveillance missions could involve a number of distinct “scan” patterns.  A point scan would involve identifying individual targets, like fighting positions and battle formations, while a raster scan would involve sweeping large swaths of territory.

“If they wanted to do strikes, they could do it right now,” the former pilot said. “But I think they’re trying to get a sense of how powerful ISIS is.”