To add TSA PreCheck to Vietnam Airlines, contact their customer service at 1-866-564-8331 or update your profile online. Traveling internationally can be stressful, especially when departing from busy airports in the United States. TSA PreCheck is a program designed to make the security screening process faster and more convenient for eligible travelers. If you are flying with Vietnam Airlines and want to add TSA PreCheck to your booking, the process requires careful attention to detail. This guide provides a comprehensive step by step explanation of how to add TSA PreCheck to your Vietnam Airlines reservation, along with helpful tips to ensure smooth travel.