According to the Department of Homeland Security's Fiscal Year 2018: Entry/Exit Overstay Report, they will be implementing facial recognition technology to identify approximately 97 percent of airport passengers departing the country. 

In its report, the DHS says, "DHS is also implementing a biometric-based departure program to complement the biographic data collection that already exists. This program matches live photos of travelers to images gathered as part of previous border crossings in order to better confirm the traveler’s identity, as well as confirm exit crossings."