On United Airlines, Group 3 is a boarding category that primarily consists of passengers seated in Window seats in the Economy cabin. United uses a boarding system known as "WILMA" (Window-Middle-Aisle), which is designed to speed up the process by seating people from the "outside in" to prevent bottlenecking in the aisles. Group 3 follows the "Pre-boarding" groups (disabled passengers, active military), Group 1 (Premier members and First Class), and Group 2 (Chase cardholders and those with priority boarding). While Group 3 is the first "general" boarding group for Economy, it is a critical group for overhead bin space. Because Groups 1 and 2 often fill the bins with their larger carry-ons, Group 3 passengers are at a moderate risk of having to gate-check their bags on smaller or completely full aircraft. If you are in Group 3, you are ahead of those in Middle seats (Group 4) and Aisle seats (Group 5), giving you a better chance of securing space for your belongings. It is important to note that if you are traveling with a companion on the same reservation, the airline will usually assign both of you to the higher boarding group (e.g., if one has a window and one has an aisle, you both might get Group 3).