I bought a Longaberger carrier from another YT member. It is plenty big enough for both of mine but still within carry-on luggage size requirements. Some airlines allow two pets if they are the same species and the total weight is not over 20 pounds. They have to be in the same carrier though, as only 1 pet carrier is allowed per person. Some restrict the 2 pets to puppies not adult dogs. I think you just have to find the airline you are using and get their specifc rules.
Ben is almost 5 pounds now, but he is short and compact. Sadie is probably about 6 pounds but she is tall and skinny as can be. She looks about twice the size of Ben, until they are wet, then you see how skinny she is. We let her have as much to eat as she wants and still she stays thin. I should be so lucky!
