I travel with very well behaved and friendly dogs. Some trips I bring just Chevy, my 12 yr old Pomeranian. Most trips I bring Chevy and my 1 yr old Great Dane mix, Hero. If possible, I also bring Rikki, my 9 yr old Weimaraner mix (only about 45#) too. I do crate Hero for rare times he may be left without us and we never leave him in crate more than 3 hours