The TSA already has your travel data from the airline PNR database [1], which stores your travel data for five years, after which it is moved to cold storage for another ten years. PNR is a contributing system as to how the TSA can provide identity proofing at the checkpoint with only an ID now, versus previously needing your boarding pass [2].

These are governance issues, not technology issues. TSA using facial recognition is no different than an agent comparing you to your ID (except that the automated system increases throughput), depending on what the exception process looks like.

[1] https://www.cbp.gov/travel/clearing-cbp/passenger-name-recor...

[2] https://www.dhs.gov/publication/dhstsapia-018-tsa-secure-fli...