In response to a question from Chairwoman Candice Miller (R-Mich.) regarding the number of inbound travelers who would be pre-cleared with the expansion, Wagner said it would bring the total up to about 36 percent of all travelers to the United States.

She asked whether the drivers are security and/or trade in selecting these additional locations. He added that four criteria including security, facilitation, feasibility and strategic impact were used to determine where the program would expand.

"We looked at the number of terrorist watchlist hits coming through that airport or originating in that airport," he said. "We looked at the number of national security concerns identified through our National Targeting Center. And then we balanced it against similar facilitation and workload measures: the number of passengers, the impact to wait times in the United States, the number of what we call secondary referrals and enforcement actions originating out of these airports."