im 21 and I have a license that says under 21 ?

Your license has your birthdate on it, right? So if they give you trouble for the license saying you're not 21, you point to the birthdate. 'Look! The license is out of date!'

Some states have a vertical license for people under 21 and horizontal for over 21, so clerks at liquor stores can check quickly. But if you just turned 21, you'll have an under-21 license so you point out the birthdate on the license.

As long as it's not explired, it's fine. However, if you plan on going to a lot of bars or buying alcohol, it might be more convenient and less embarrassing to get the id updated but I'd wait until after your trip. That's the main reason for the Under 21 designation is for alcohol, not flying

Assuming you mean you have a vertical license as is issued to people under the age of 21 you can still use it after your 21st birthday. If you use it to buy alcohol then you need to ask the cashier to check the DoB on your license and not just look at the vertical type license.

This is a common situation and you don't need to stress over it.

If it shows your date of birth, it's gonna be OK

The humans can if necessary actual read the date of your RECENT Birthday and figure it out.

It is set up that way to reduce your ability to enter liquor facilities NOT AIRPLANES.
Get your new replacement when you return.

IF your ID is not expired, then you don't need a new one.
It clearly says your birth date, so any sensible person will be able to tell that you are over the age of 21.
Most IDs have in bold that a person is under 21 until their birthdate, and it is very clear and easy to see. Any person who knows the date will be able to tell that you are over 21.

If the ID is not expired, then it is considered valid ID. A temporary ID is a paper ID that you receive while waiting for your permanent ID to arrive. You cannot use those paper IDs for air travel, but a permanent ID is fine.

YOUR choice. You can go to the DMV and PAY to get a new "adult" license, or just continue using the old one until it expires.

This isn't rocket science. As long as the license isn't expired, your age is irrelevant for flying.

You can fly by yourself from age 15 with ID. That your license says you are under 21 is not a problem.

If the drivers license is not a REAL ID license then you can not use it for flying anyway. I would go to the DMV and get it updated.

Strange

Go get it updated

Just use your old one, typically when someone checks an ID the have to look at the date of birth. They cant refuse you as long as your liscense isnt expired. Just tell them your date of birth shows you are 21 even though it's on an under 21 liscense

Unless you have some other acceptable form of ID, you are going to have to hold onto your 'under 21' ID until your trip is finished. If you want to buy alcohol before you can get a new ID, then you are a going to have to deal with the fact that some places won't take IDs that say 'under 21' or vertical IDs.

It DOES expire. Take another look at it. If the dob is wrong, you should get it fixes asap.