A report released by the Federal Aviation Administration this week reveals an 81 percent increase in air traffic controller errors between 2007 and 2010.

The data, released on Monday, involved errors that caused planes to fly too close to each other.

The FAA attributes the increase to changes in the way errors are reported and categorized, but some critics blame other problems, such as inexperienced staff and inadequate training.

Nearly half of all air traffic controllers in the U.S. have been hired in the past five years because a large number of air traffic controllers have recently retired.

Congress has requested a Department of Transportation report into the increase in errors, which is expected to be released in the spring of 2012.