( CNN ) -- The effects of an employee 's alleged sabotage of the Illinois air traffic control center where he worked continued to be felt by air travelers through the weekend . By Saturday afternoon , more than 660 flights scheduled to either take off or land at Chicago 's O'Hare International Airport were canceled , according to the Chicago Department of Aviation . Another 120 had been canceled over at the city 's Midway Airport . The disruption stems from a Friday morning fire at the FAA Chicago En Route Center in nearby Aurora , a critical air traffic control center . Police say that blaze was set intentionally by Brian Howard , a contract employee at the facility , before he apparently attempted to kill himself . An FBI affidavit says that a first responder saw some feet sticking out from under a table and found a shirtless Howard `` in the process of actively slicing his throat with another knife . '' He told paramedics to `` leave me alone , '' the affidavit said . He survived and was taken to an area hospital . His condition was not available Saturday . He 's charged with one count of destruction of aircraft or aircraft facilities , a felony that could land him a 20-year prison sentence . No court date has been set . Ominous Facebook message . According to the FBI , Howard , 36 , had worked at the center for eight years but was facing a transfer to Hawaii . In a private Facebook message sent to a relative just before the fire , he wrote `` Take a hard look in the mirror , I have , '' the message said , according to the affidavit . `` And this is why I am about to take out ZAU [ the three-letter identification for the control center ] and my life . ... So I 'm gon na smoke this blunt and move on , take care everyone . '' Then , at 5:40 a.m. , Howard -- who worked in `` telecommunications matters , '' according to the FBI -- apparently started the fire in the control center 's basement , causing the facility that controls flights in several Midwest states to evacuate and shut down . The effects were immediate . O'Hare -- the second-busiest airport on the planet according to Airports Council International -- is a main hub for United Airlines and other major carriers , with flights headed to international destinations . When controllers stop flights scheduled to there , it has the potential to trigger a line of falling air-traffic dominoes that will ruin travel plans for countless would-be passengers . By Friday evening , more than 2,000 flights had been canceled in and out of Chicago 's two airports . The ripple effect caused disruptions at airports across the nation . Southwest Airlines suspended all fights Friday not only in Chicago , but at Milwaukee 's General Mitchell International Airport as well . Hartsfield-Jackson Atlanta International Airport had 70 cancellations and there were 56 at New York 's LaGuardia Airport . FAA divvies up Chicago air traffic control . The FAA said that a clean-up crew was brought in Saturday `` to begin drying out water-damaged equipment '' in the telecommunications room where Howard set the fire , as well as to clean and sanitize the area after the attempted suicide . But just when ZAU will be fully operational again is not yet known . `` Technicians also are completing a thorough damage assessment and timeline for restoration of services , '' the agency said Saturday . `` The FAA is using all the tools at its disposal to safely restore as much service as quickly as possible . '' The FAA said over the weekend that it was managing the air traffic in and out of Chicago `` through other large Terminal Radar Approach Control ( TRACON ) facilities in Illinois , Indiana and Wisconsin with additional help from high-altitude centers in Minnesota , Kansas , Indiana and Ohio . '' In the meantime , the FAA said ZAU 's displaced employees `` are assisting at the TRACON facility in Elgin , Illinois and other air traffic facilities . '' CNN 's Ralph Ellis , Jason Hanna , Thom Patterson , Mike Pearson , Amanda Watts , and John Newsome contributed to this report .
NEW : FBI clean-up crews assessing damage at key air traffic control center . Employee allegedly tried to 'take out ' Chicago En Route Center while attempting suicide . two of flights at Ohio and Midway Airport airports canceled since . Mike Pearson effects felt at airports across the country .