 A record number of Americans took flight over the holiday weekend as the summer travel trend continues. The TSA expected Sunday to be its busiest day ever, and it was. Preliminary numbers show that more than 3 million people passed through security checkpoints at U.S. airports for the first time ever in one day. The numbers have spiked during the summer travel season. Overall, the TSA projected screening 32 million people from the end of June through today. ABC's Brian Clark.