The glitch, which occurred about 5 a.m. EST, prevented airlines from electronically entering their flight plans into a FAA computer in Salt Lake City that air traffic controllers around the country rely on for information. FAA officials blamed a failed circuit board in a networking system that is used to transfer flight data. Before it was corrected four hours later, air traffic controllers had to type up flight plans instead of obtaining them electronically, which slowed the air transportation system. An FAA computer center in Atlanta as well as 21 regional radar centers around the country were affected, officials said. Hit hard by the problem was Hartsfield-Jackson Atlanta International Airport, the world's busiest commercial airport. The glitch aggravated delays caused by bad weather in the Northeast, while airports in Chicago, Washington, D.C., and other parts of the South experienced cancellations and scheduling problems. Some flights were postponed more than two hours and on-time arrivals for some airlines plunged as much as 40 percent, according to information from FlightStats.com. AirTran canceled more than 30 flights and delayed scores more. Delta Air Lines canceled at least 54 flights and the operations of jetBlue Airways' slowed on the East Coast. American Airlines also delayed several hundred flights, company officials said. 'Operations are slowly returning to normal and we are working with impacted passengers,' Ed Stewart, a spokesman for Delta, said Thursday afternoon. 'Cancellations and delays are fairly minor, although we are continuing to assess our operations.' In response to Thursday's delays, U.S. Sen. Charles Schumer, D-N.Y., issued a prepared statement, saying the country's aviation system is 'in shambles' and the FAA needs more resources to prevent future problems and to modernize its equipment. 'If we don't deliver the resources, manpower, and technology, these technical glitches that cause cascading delays and chaos across the country are going to become a very regular occurrence,' he said. In August 2008, an electronic communication failure at an FAA site that processes flight plans for the eastern U.S. caused massive air traffic delays, especially in the Northeast. FAA officials blamed the malfunction on a software problem at a facility in Hampton, Ga. Ian Gregor, an FAA spokesman in Los Angeles, defended the agency, saying its equipment has been 'extremely reliable' and, on average, is in service more than 99 percent of the time. 