Why would you not contact the airline??
https://www.faa.gov/faq/do-minors-need-identification-Do minors need identification to travel?
Each airline determines identification requirements for minors. Contact your airline well in advance of your travel date to determine if they have unique policies or procedures for minors.
Typically, minors under the age of 18 do not have to present identification for domestic U.S. travel. Airlines will accept identification from the responsible adult on behalf of the minor(s).