The main changes since the last time you flew involve all those other places that used to not require a passport. e.g. Whereas previously it was possible to visit Canada or Mexico with just a driver's license, you now need a passport.
Within the US, AtlasRN is 100% correct. Your driver's license will be sufficient. What you will find different these days is the amount of security checks, scans and restrictions. You will be wise to wear shoes that are easy to remove, read up on the restrictions for carrying liquids in your carry-on bags, carry electronics (especially laptops) in a bag that makes them easy to remove, and allow extra time for getting through security.