The U.S. Transportation Department said on Tuesday more than 11,000 employees at the Federal Aviation Administration will be furloughed if government funding lapses at midnight.

U.S. airlines have warned that a partial federal government shutdown could strain American aviation and slow flights, as air traffic controllers and security officers would be forced to work without pay and other functions would be halted.

n employee with the Transportation Security Administration (TSA) checks the documents of a traveler at Reagan National Airport in Washington. REUTERS/Joshua Roberts

The Transportation Department said the FAA would continue to hire air traffic controllers, and field training of controllers would continue. During prior government shutdowns, the FAA suspended hiring and most training of air traffic controllers.

More than 13,000 current controllers would be required to continue working, but would not be paid until the shutdown ended, the FAA said.

The FAA has about 45,000 employees. In total, the Transportation Department would furlough 12,200 employees out of 53,717, including the FAA.

The FAA also said certification activities would continue for operational safety functions of commercial airplanes and engines, as well as commercial space launch oversight and licensing.