I once flew from Montreal to Washington, DC and there was secondary screening at the gate. I held up the flight because airport staff didn’t know the procedures on how to handle my SSSS flag.

I called DHS about getting off the list and after getting bounced around a few times I was told:

- I was not on the no fly list, which DHS does actively maintain

- DHS manages and publishes selection criteria which is pushed down to airlines. What the airlines do with it and when they do it is their own process independent from DHS

- I could submit my driver’s license, proof of address, address history for exclusion, as well as any additional information requested after the initial submission.

- DHS would review and update the parameters, but it would be 6-12 months before the database update fully took effect with the airlines.

I stopped flying that one airline 16 years ago.