WASHINGTON (Reuters) -The head of a trade group representing major U.S. airlines told Reuters on Wednesday carriers are beginning to see a drop-off in passenger bookings as a government shutdown hit a record 36th day on Wednesday.

"We started seeing as an industry pull back on folks booking their travel plans just over a week ago and it's growing a little bit every day," said Chris Sununu, who heads Airlines for America that represents American Airlines ( AAL ), United Airlines, Southwest Airlines ( LUV ), Delta Air Lines ( DAL ), JetBlue Airways and other major carriers, adding carriers are not seeing a jump in cancellations.

"We're trying to encourage people to stick with their bookings, stick with their travel plans."