United Airlines does allow carry-on pets, such as small dogs and cats that meet specific requirements. There's a weight limit for the pet and carrier, along with carrier dimension rules. A fee is applicable, and reservations are necessary, as there are limited pet spaces per flight. Ensure your pet meets health and documentation requirements. For detailed information about United Carry On Pet, visit Airlinespetpolicy website or contact customer service for a smooth journey with your furry companion.