Obviously, DL issues boarding passes all the time without checking any ID... either via the kiosks or else with online check-in. Many previous posters on this thread have given the right answer... worse case scenario, you get steered into extra security (SSSS) if you have no valid ID. An expired license or passport may or may not be noticed, but you will not be denied entry through the checkpoint, just an extra look.
Remember, all the hijackers on 9/11 had boarding passes and IDs. The entire exercise is all but meaningless.