ARLINGTON, Va. – Aviation worldwide remains under constant threat of terrorism, but intelligence gathering helps reduce the risks to travelers, the head of the Department of Homeland Security said Friday as he toured Washington Reagan National  Airport before what is projected to be a record summer for airline travel.

John Kelly met with federal security director Kerwin Wilson and spoke with TSA officers at a checkpoint as passengers streamed toward their flights on the eve of Memorial Day weekend. But lines were moving briskly and Kelly said TSA was moving 90% of travelers through checkpoints in an average of 5 minutes or less, with the rest getting through in less than a half-hour.

"We have worked out an awful lot of bugs through the years," Kelly said. "Let's be vigilant and patient."

Kelly is considering expanding to more countries a ban on laptops in carry-on bags that now applies to direct flights from 10 airports in the Middle East and Africa, but he didn't have a time-frame for when changes could be announced. The concern is that terrorists have found a way to better hide a bomb in electronics larger than cellphones.

"We'll make a decision when the time is right," said Kelly, who is working with airlines and security officials in Europe in Asia to improve aviation security worldwide.

"The threats against passenger aviation worldwide are constant," Kelly said. "The good news is we have strong intelligence collection overseas."

Kelly said a new TSA administrator is expected to be named soon, but that nobody should be worried about the lack of a political appointee at the agency because of the professionalism of the staff.

TSA prepare for the heavy travel period from Memorial Day to Labor Day by fielding 50 more canine teams and 2,000 more checkpoint officers this year. TSA will coordinate checkpoint staffing with airlines through its Airport Operations Center.

“As we approach the summer break, securing the travel of millions of passengers daily remains our top priority,” TSA Acting Administrator Huban Gowadia said Wednesday. “It is well known that terrorists continue to focus on aviation, which is why TSA continues to focus on providing robust security screening.”

The additional staffing came after long checkpoint lines in spring 2016 sparked complaints across the country. Congress agreed to allow TSA to shift funding to boost staffing, and airlines and airports provided more staffers to shorten the lines.

Kelly’s airport visit came at the start of a travel season where airlines expect traffic to grow 4% from last year.

A record 234 million passengers, or 2.54 million per day, are projected to travel worldwide on U.S. airlines from June 1 through Aug. 31, according to Airlines for America, a trade group representing most of the largest carriers. The total compares to 224.8 million last year.

Airlines are adding 123,000 seats per day to accommodate about 100,000 extra daily passengers during this period.

“We continue to see consumers value experiences and travel, and airlines are responding accordingly by increasing staffing and boosting the availability of seats in the marketplace, as well as further investing in new aircraft and customer-facing technology,” John Heimlich, the group’s chief economist, said in announcing the estimates May 18.

TSA offered tips for getting through security smoothly:

♦Pecheck and other trusted-traveler programs, such as Global Entry, offer expedited lanes where travelers can keep on shoes and belts, and leave laptops and small containers of liquids in their carry-on bags.

♦On Twitter, travelers can comment to @AskTSA or ask questions from 8 a.m. to 10 p.m. on weekdays and from 9 a.m. to 7 p.m. on weekends and holidays.

♦For travelers with disabilities or medical conditions, call TSA Cares at 855-787-2227 at least 72 hours before a flight with questions about screening policies, and to learn what to expect at the checkpoint.