Are you planning to book your United Airlines flight tickets? You should be aware of the United Airlines baggage policies. United Airlines allows customers to bring one personal item and one carry-on. Your personal item and carry-on must fit within the overhead bin. A carry-on bag's maximum dimensions are 9 inches x 14 inches x 22 inches, with handles and wheels. Personal items should not exceed 9 inches by 10 inches by 17 inches. They must be placed underneath your seat.