What is the requirements to fly from CA to TX

@dunni's answer is technically correct, but let me amplify. The United States is one country and there has not been a need for a visa or permit to go from one state to another, ever. (OK: except crossing military lines during the Civil War.) You need identification to get on an airplane flight. Acceptable forms include either your passport or your Green Card. The status of drivers licenses is changing, as some states' licenses will be deemed insufficiently secure. California will has just started offering Real ID, but your existing license probably does not qualify and will not be accepted after October 1, 2020.

As long as you don't leave the USA by having a stopover in another country, while flying to Texas, your existing green card and passport are enough (not sure, if the driving license alone would be sufficient as identification, i read something about some changes there). But with the passport and green card you are definitely fine.