Passengers flying with Spirit Airlines from the Las Vegas terminal should arrive at least two hours before a domestic flight. The check-in counters for Spirit are located on Level 2 of Terminal 1. Given the airline’s low-cost model, many travelers check in online in advance or use the self-service kiosks to save time and avoid long lines. Security checkpoints in Terminal 1 can get busy, especially during peak hours or major holidays. TSA PreCheck is available for eligible travelers, helping speed up the process for frequent flyers.