Security tight at Hartsfield-Jackson air traffic control tower

But, "when we do have requests for people to bring their families in, it's for a brief period of time -- maybe 30 minutes," Bergen said. She said children do not visit after hours, and the vast majority of visitors are there for FAA business.

Hartsfield-Jackson, the world's busiest airport, has the tallest air traffic control tower in North America and the third tallest one in the world. But school groups and church groups generally cannot visit the tower, she said.

"At the world's busiest tower, we cannot have visitors who are not business related," Bergen said. "Any visits that would be non-business related would have to have some link to the facility."

Visitors to the tower must get written approval in advance from a manager or a manager's designee, Bergen said. Visits are normally restricted to certain  hours -- such as before 9 a.m. or between noon and 2 p.m., she said. Bergen said she does not approve people for same-day visits.

After getting to the tower, visitors must go through "airport-type" security and adults must show photo identification, she said.

An air traffic controller and supervisor are on administrative leave while the agency investigates the incident at Kennedy Airport when a child communicated with pilots on an air traffic control frequency. A team will review air traffic control policies and procedures on visits to facilities, according to the FAA.

On Wednesday, the FAA announced that all unofficial visitors to FAA air traffic control operational areas, including towers and radar rooms, have been suspended pending the investigation.