US airports are not set up to handle exit immigration because domestic and international departures occur in the same secure areas of the airport and those areas are not sterile, meaning that any departing passenger can walk out of the departures area and remain in the USA. In the USA, only international ARRIVALS areas are sterile. There are no in-transit areas currently operating for commercial air travel.

As a result, the vast majority of travelers have no passport exit controls when departing the USA.

The only exceptions are for those subject to the NSEERS procedures, who must report to a CBP officer for an exit interview before being permitted to leave the country.