The 20-inch boarding box is smaller and more convenient to carry, which is suitable for business travelers and travel enthusiasts who often fly. At the same time, the weight of the 20-inch boarding box should not exceed 7kg, so as to comply with the regulations of airlines.
In contrast, although the 24-inch boarding box can also be taken on the plane, it may not be placed on the luggage rack on the seat because of its large size, and it needs to be placed in front of the seat or on the ground, which will increase the inconvenience of passengers. So the 20-inch boarding box is more suitable for passengers.
It should be noted that different airlines may have slightly different regulations on the size of boarding boxes, but generally speaking, 20-inch boarding boxes are in compliance with the regulations. If you need more specific information, you can check the airline official website or consult the customer service staff.