reporter: the tsa says more than 2 million people passed through airport checkpoints saturday. the number of flyers close to pre-pandemic levels. those lines are going to take longer. add to that lingering staffing shortages and you have a recipe for long lines and delays. reporter: the vaccination mandate for federal workers taking effect tomorrow, sparking fears of airline and airport staffing shortages. but today transportation secretary pete buttigieg confident that holiday travelers will not be impacted. the deadline tomorrow, that s not a cliff. people aren t getting immediately pulled off their posts. it s part of a process to make sure that everyone in the federal workforce is safe. reporter: the busiest airports this weekend, atlanta, dallas, and los angeles. if you plan to drive you will have plenty of company as well. aaa is expecting more than 48 million people will hit the roads this week. the price of gas right now is ridiculous, so every cent counts. report