You do not need a passport to fly domestically. You don’t even need any ID at all although having one makes flying much simpler and easier. You must have a passport to fly internationally.
“You don’t even need any ID at all although having one makes flying much simpler and easier.”
I never flown without have to show ID to get pass security (states, not international). I have been flying for decades. Also, this year the airline screwed up my birthday when I purchased my ticket by one day. I am over 65 years old and had to go to airline counter to change the date from 4/8 to 4/9 or they would not let me pass security.