The controller's union, which is locked in a contract battle with the FAA, says some facilities are too short-staffed with veteran controllers and have far too many trainees.
Earlier this year, the Department of Transportation's inspector general reported that as of December 2007, 22 percent of air traffic control facilities exceeded the FAA limit for trainees.
"I wouldn't go so far as to say it's not safe," union president Pat Forrey told "Good Morning America." "I think the margin of safety has definitely decreased."
The FAA acknowledges that some facilities have had too many trainees and says it's working to try to change that. But the agency insists its recruits are top notch.
"These folks are motivated," said FAA acting administrator Robert Sturgell. "They're technology savvy and they're ready to go. And they're getting the best training out there for air traffic control. "
Instructor Chris Brannen has one main goal for his students.
"More than anything else, is confidence," Brannen said. "I want them to leave this course with all the confidence in the world -- where they can go out and be successful in the field." Rachel Klouse will need that confident attitude. She's now passed her initial course and is heading to the busy Los Angeles airport for her on-the-job training.
"I definitely believe that it will be [a challenge]," she said. "They have a very high washout rate there, so not everybody makes it."
Barker will begin at the much smaller airport tower in Corpus Christi, Texas. Before he gets there though, he's happy to have practiced with the model planes, knowing how critical it is that everything goes right.
"Here, if I mess up, it's just two kids run their hands together," he said. "So you want [to] mess up here before you go out there and mess up."