One reason for the expanded program, the agency’s administrator, John S. Pistole, said, is to “make sure that the T.S.A. PreCheck lanes are being fully utilized” throughout the day, rather than just at peak hours. In a year-end report to employees, Mr. Pistole cited as an example what occurred at the Indianapolis airport on the day before Thanksgiving. Nearly a third of all passengers were chosen to go through a dedicated PreCheck lane, rather than the usual less than 5 percent, he said.