I'am going to vega in June and someone told me that I need a passport to travel within the united states.

Here is a link to a similar thread:
do you now need a passport to travel within the united states? (https://www.askmehelpdesk.com/visas-passports/do-you-now-passport-travel-within-united-states-57094.html)

Sarah

Are you flying in from Canada ? Where you are coming from to come to the US is one question

Travel from one point in the US to another point only requires a proper ID

Assuming that you are a citizen of the US, traveling completely within the US, you need some form of government issued picture ID - not necessarily a passport.

If you live in the US and you're traveling within the US then no you shouldn't need a passport.