Transportation Secretary Ray LaHood said two air traffic controllers who have made mistakes in recent weeks have been fired.
In an interview Wednesday evening on PBS's "NewsHour," LaHood said he was taking steps to staunch the string of reports about controllers neglecting their duties.
LaHood said one controller worked in Miami, Fla., and one worked in Knoxville, Tenn. He called their transgressions unacceptable.
"Miami, Fla., where the controller had guided a 737 Southwest flight to take a look at a small plane that was out of radio contact to see if something was going on," he said. "Completely violates procedures. You can't guide a big plane over to look at a small plane. That's not the way that's done.
"Also, in Tennessee, where a controller actually made a bed in the control tower, brought a pillow, brought blankets," LaHood continued. "He's been fired. We're not going to sit by and let that kind of behavior take place in control towers."
LaHood said despite the rash of reports of controllers sleeping on the job, the problem has not been widespread.
"I have been in this job two-and-a-half years, and the first time I have heard about a sleeping controller is when it happened at Washington National Airport," he said.
LaHood also addressed an incident this week involving a plane carrying first lady Michelle Obama, which had to abort a landing because a military cargo plane had not fully cleared the runway. LaHood said proper procedure was followed there once the error was discovered.
"It was too close to the cargo plane, and that was disclosed," LaHood said. "And the controller that was in charge made sure that her plane made the corrective moves.
"I want to assure everyone that Mrs. Obama was never in any danger," he said.
Still, LaHood said flights carrying the first lady and the vice president would now be monitored in the same way as flights carrying the president.