Enroute CPDLC is now live for all of US domestic airspace. L3 Harris has a CPDLC portal that is your go-to source for applying and learning about the new procedures.

In the ADS-B era, any ADS-B equipped aircraft is trackable. There are several steps you can take to increase your privacy via FAA programs: CARES, LADD, and PIA. None of the programs offers an entirely anonymous solution. To travel compeley incogneto, don't own an ADS-B transponder.