Govt. agency whose busiest days usually precede major holidays

TSA

Think of the long lines you endure before flying out for Thanksgiving or Christmas.

This clue points to the TSA, or Transportation Security Administration, the U.S. government agency that handles airport security. Their busiest times are right before major holidays like Thanksgiving or Christmas, when millions of travelers pass through checkpoints. The phrasing "busiest days" hints at the long lines and extra screenings that happen during peak travel seasons. It’s a straightforward reference to real-world patterns most people recognize.