Austin-Bergstrom International Airport is entering one of the busiest stretches of the year just as a partial shutdown of the federal government threatens to slow TSA screening lines. Tens of thousands are expected to pour through Austin's airport to catch this year's lineup which includes Hozier, Sabrina Carpenter and T-Pain. The U.S. Grand Prix returns to Austin Oct. 17-19 this year, bringing tens of thousands of fans to Circuit of the Americas. The Monday after the race was the busiest day ever recorded at ABIA for the last three years in a row. For comparison, on Wednesday, a relatively calm day at ABIA, the TSA was expecting to screen about half that number.