Airspace over Port-au-Prince International is packed with planes and helicopters bringing disaster relief.

There is no longer a control tower, and, at times, aircraft are forced to circle overhead for hours and wait for a chance to land on the runway, which is overflowing with emergency vehicles bringing medical supplies to the injured. It's difficult to tell whether they are alive or dead.

U.S. Coast Guard and Air Force members are directing flights in and out -- standing by the runway using radios.

Smoke billows in the distance on the hillside where the capital city of the Western Hemisphere's poorest country once stood -- swallowed by a massive 7.0-magnitude earthquake and battered by dozens of strong aftershocks. As planes descend, the crumbled buildings and rubble appear to crew members.

And then you see them, the thousands of people wandering the streets aimlessly with horrific expressions of absolute terror and distress who are searching for loved ones.

That's what pilot Michael Raymond saw Thursday afternoon as he flew in 37 rescue workers and seven search dogs from Miami to Port-au-Prince. The Boeing 737-400 then was loaded with 57 Americans, one of whom had suffered a back injury, to return to Miami.

Airline employees have volunteered to fly supplies and bring back citizens to the United States. At least three Vision Airlines flights from Atlanta and Miami have made the three-hour round trip. Most have been delayed as planes wait their turn to land on the tiny airstrip.

"When we had landing assured and you started recognizing streets, you see these thousands of people with a sense of hopelessness, they're just devastated," Raymond said. "As you were flying in, at the border of the airport, you can see people begging to get out of there."

At one point, Raymond and his crew had to circle for two hours, it was a "scary thing" for the pilot.

"You always plan ahead for holding, so we had plenty of fuel, but then we had to hold for so long," said Raymond, who has 31 years of flying experience. "Fuel became critical."

There are places to get fuel in the Dominican Republic, he added.

"It's a tough job," Raymond said. "There's a whole gamut of emotions as you're looking at workers coming up and down. You'll see a person lying on a stretcher with IVs and you don't know if they're dead or not."

The biggest challenge for the crew in North Las Vegas is air traffic, said Jason Tolman, director of systems operations control for Vision Airlines. Usually the team manages sightseeing flights over the Grand Canyon.

"We're communicating with airplanes and just trying to get as many flights down there with relief workers on board," Tolman said. "Everybody is eager to help out and doing whatever is necessary, but it's very stressful with long days and demanding issues. Big decisions need to be made under pressure, and that's the hardest part."

As of right now, Vision Airlines is planning to make planes available for disaster relief indefinitely, Tolman added.