Updated January, 2020:
US TSA just announced ALL US CITIZENS must provide either a valid “REAL ID” **, passport, or Military ID … by October, 2020 … to be able to fly on any US domestic flight … regardless of your home State.
** https://www.tsa.gov/real-id
Per the USA’s “Real ID Act” …. One must use either a passport … or officially approved “Enhanced ID” … to take a US flight…
In other words …if your USA driver’s license does NOT have a gold or black star on the front of the license … then you are generally NOT “good to go” – and NEED to use a Passport.
Notice that to make it more confusing, a few states have issued REAL ID Act compliant IDs … without a star => Hawaii, Ohio, Tennessee, and Utah have compliant Driver’s licenses, without a star.
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Feel free to copy while giving proper attribution: YucaLandia/Surviving Yucatan.
© Steven M. Fry
Read on, MacDuff.
Surviving Yucatan 
defund the TSA… worthless agency
Awww… C’mon ….
They only had 450 TSA ’employees’ prosecuted for criminal acts … creating the odd situation where TSA employees have committed far more harmful criminal acts ~than they have stopped~ .
… and … Every year since their creation, when our real police (the Air Marshals) go under-cover, and attempt to smuggle guns & big knives through the TSA Checkpoints – the TSA Keystone-Cops fail to detect the weapons over 90% of the time … allowing 2 decades of nasty illegal weapons through their supposed checks…
😦
OK, pardon me for my negative comment.
Give them a bunch more money, healthcare and food for the populace is unimportant.
(archaism)
opps: sarcasm
Last time I renewed my regular passport, I paid extra to get a credit card size passport card to have in my wallet. I used that card, my last 1099 and some utility bills, (how Mexico is that?), to get my ‘real id’.
actually that passport card is a Real ID. you don’t need more. Passport “booklet” is not necessary. However many TSA agents are not well informed and may give you some grief… as they did me, even if you offer open your bag to show the booklet.
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Under the REAL ID Act, the passport card is accepted for federal purposes (such as domestic air travel or entering federal buildings) https://travel.state.gov/content/travel/en/passports/apply-renew-passport/card.html