Travellers in Economy on United Airlines are allowed to bring one normal carry-on bag and one personal item by Carry on rules for united. The maximum size for a carry-on bag should be 9 inches by 14 inches by 22 inches (22 cm by 35 cm by 56 cm). The private thing needs to fit beneath the seat. Bigger or more carry-on bags could be permitted in first class and business class cabins, among other premium categories. For up-to-date and detailed information, visit United Airlines' official website or get in touch with the airline. Carry-on policies can change according on the fare class and route.