U.S. economic growth in the fourth quarter could be negative if a federal shutdown drags on, White House economic adviser Kevin Hassett said in an interview that aired on Sunday.

Hassett, speaking to the CBS show "Face the Nation," noted that a shortage of air traffic controllers was causing major travel delays in the run-up to the Thanksgiving holiday.

"Thanksgiving time is one of the hottest times of the year for the economy... and if people aren't traveling at that moment, then we really could be looking at a negative quarter for the fourth quarter," he said.