The court decided that presenting identification at the airport does not violate your constitutional rights:
Airline personnel’s request for Gilmore’s identification was not a seizure within the meaning of the Fourth Amendment. Gilmore’s experiences at the Oakland and San Francisco airports provide the best rebuttal to his argument that the requests for identification imposed a risk of arrest and were therefore seizures. Gilmore twice tried to board a plane without presenting identification, and twice left the airport when he was unsuccessful. He was not threatened with arrest or some other form of punishment; rather he simply was told that unless he complied with the policy, he would not be permitted to board the plane. There was no penalty for noncompliance.
There it is: There is no penalty for noncompliance. You can show ID, or you can not get on the plane.
But, the court notes that Gilmore was given an alternative by both United Airlines and Southwest Airlines. If he did not want to show ID, he could have choosen to be a "selecteee," by which he would be subjected to an "additional search." The court decides that the additional search was reasonable:
To meet the test of reasonableness, an administrative screening search must be as limited in its intrusiveness as is consistent with satisfaction of the administrative need that justifies it. It follows that airport screening searches are valid only if they recognize the right of a person to avoid search by electing not to board the aircraft.
Gilmore was free to reject either option under the identification policy, and leave the airport. In fact, Gilmore did just that. United Airlines presented him with the “selectee” option, which included walking through a magnetometer screening device, being subjected to a handheld magnetometer scan, having a light body patdown, removing his shoes, and having his bags hand searched and put through a CAT-scan machine. Gilmore declined and instead left the airport.
Now the court is giving Gilmore three options: You can show ID, you can be a "selectee", or you can simply not get on the plane. According to the court decision a "selectee" must:
A) Walk through the magnetometer
B) Get the handheld magnetometer scan
C) Get a patdown
D) Take off his/her shoes
E) Have his/her bags searched by hand and CAT-scanned
This makes me wonder: Is Gilmore vs. Gonzales even relevant? This decision was made in December 2005, but the last time I flew I was made a "selectee" and I DID show my ID. I politely showed the TSA officials my Oregon drivers license when they asked, and then when I walked through the magnetometer screening device like everyone else they took me asside and perfomed B, C and D on me while they did E on my laptop bag.
If you're going to be made a selectee anyways, you might as well not show your ID and at least anonymously have your privacy violated.