Of course, the men are just guessing as to whether an aircraft on the screen may be attacking or simply reconnoitering the positions of troops loyal to Muammar Qaddafi and the rebel forces arrayed against them. NATO doesn't communicate with the control tower, though it could help the rebels coordinate attacks on Qaddafi's forces, and the radar displays no terrain features or live satellite view.

Instead, the monitor is filled with white diamonds silently moving across a black background. The planes fly across colored lines indicating Libya's coast and purple four-letter abbreviations of cities. Numbers indicating speed and altitude accompany the diamonds on their flight paths.

Typical aviation codes that tell controllers the type and origin of airplanes in Libya's airspace have been replaced with numbers unique to NATO. The men, civilian air traffic controllers unfamiliar with the military jets, can't tell what types of planes they're watching.

But they can guess when they might be attacking. If a plane's airspeed suddenly slows and its altitude plunges, it's probably striking something.

"Whenever an aircraft is going down to the lower level, we presume the aircraft is going to strike," said the air traffic control supervisor as he puffed on a cigarette. At another terminal, three men with Kalashnikovs, the facility's security guards, watched the screen with fascination.

Another clue that a strike may be underway is when a plane turns off its transponder, which broadcasts aviation information to the control tower. In that instance, the diamonds turn to circles, with no information about their speed or altitude.

"We presume that that has indicated the aircraft has gone down to strike," the supervisor said.

Around noon that Monday, most of the NATO traffic was over the Mediterranean, cruising at altitudes above 30,000 feet. But there were also aircraft flying lower around the besieged rebel enclave of Misurata, the government stronghold of Surte, and along the eastern front between Ajdabiya and Brega, where airstrikes took out a column of government vehicles the day before. The airstrike -- and others throughout the mid-April weekend -- aided rebels in regaining control of Ajdabiya, the critical crossroads city on the rebel frontier, which they still hold.

Like much else related to the two-month old rebellion, members of the opposition government aren't sure how to capitalize on the real-time intelligence gleaned from the civil radar. Air traffic controllers say their former military counterparts -- with whom they worked side by side in peacetime, as the airport also handles military air traffic -- sometimes use cell phones to call rebel commanders in the field to tell them when it seems an airstrike might be underway. On most days, a high-ranking member of the Transitional National Government also spends the day observing the radar.