You have the right to try and fly without an ID. The airlines also have the right to tell you to buzz off and get lost and the airport operator has the right to decide they don’t want you in the building and trespass you if you don’t scram.
This isn’t like the 1st amendment.
Public carriers like airlines are not allowed to refuse service for the reason of refusing to show ID.
They can refuse for other reasons, but the are not “in the loop” when passengers currently get screened by the TSA, which is where RealID is “required”.
The airlines are not in charge of airport security. TSA, a government agency, handles that.
You have an absolute "right to travel" (see the 14th amendment and other cases as recently as 1999), but you're also absolutely correct that "common carriers" can can refuse commercial service and you can be criminally trespassed from an airport, BUT TSA can not charge you a fee to attempt to fly.