There are widespread flight cancellations and delays nationwide because of a problem with the FAA system that collects airlines' flight plans.

FAA spokeswoman Kathleen Bergen says she doesn't know how many flights are being affected or when the problem will be resolved.

An AirTran Airways spokesman says there's no danger to flights in the air, and flights are still taking off and landing.

However, spokesman Christopher White says flight plans are having to be entered manually because of a malfunction with the automated system.

As a result, there are delays and cancellations.

Hartsfield-Jackson Atlanta International Airport, the world's busiest airport, has been particularly affected.