WASHINGTON (Reuters) -A group representing major U.S. airlines warned on Monday 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.

Airline trade group Airlines for America, which represents United Airlines, Delta Air Lines ( DAL ), American Airlines ( AAL ), Southwest Airlines ( LUV ) and others, warned that if funding lapses "the system may need to slow down, reducing efficiency" and impacting travelers.