There have been at least five reported incidents of air traffic controllers falling asleep on the job in the last two months, which has prompted negotiations between the government and the controllers' union to change the way controllers are scheduled to work.
The FAA has acknowledged there is a widespread problem with fatigue among controllers and that the agency is taking steps to improve the situation, including an additional hour of rest and changing their schedules so they cannot work a three-day weekend.
Transportation Secretary Ray LaHood told ABC News today he is "hopping mad" about these recent incidents and that the agency "will just not tolerate it from our controllers."
"Guiding planes full of people in and out of airports is serious business. And so my reaction is I'm hopping mad about it and we will continue to suspend controllers and doing investigations until we put a stop to this," he said. "My idea is zero tolerance for this kind of behavior -- zero."
Feb. 19: A controller in Knoxville, Tenn., went to sleep on the job during a midnight shift. Sources told ABC News that the controller made a bed on the floor of the control tower with couch pillows.
March 23: A controller on his fourth consecutive overnight shift at Washington, D.C.'s Reagan National Airport left the radio tower silent after apparently falling asleep. Two commercial airliners were forced to land on their own.
March 29: Two controllers at Preston Smith International Airport in Lubbock, Texas, did not hand off control of a departing aircraft to another control center and it took repeated attempts for them to be reached.
April 11: A controller at Boeing Field/King County International Airport in Seattle fell asleep on the job. Boeing Field does not handle any commercial air travel.
April 13: A controller at the Reno-Tahoe International Airport in Nevada was sleeping as a plane carrying a crticially ill patient was trying to land.
April 16: An air traffic controller fell asleep on the job at an air route control center in Florida.
April 17: An air traffic controller near Cleveland was suspened after being caught watching a movie -- Samuel L. Jackson's "Cleaner" -- on the job.
ABC News' Huma Khan and Sunlen Miller contributed to this report.