I am currently looking for a female yorkie, I have a little male and I think he would be much happier with a playmate as well. Bailey has so much energy and loves to play with my bf's dogs, but they are older and bigger and really can't be bothered, poor Bailey gets frustrated with them!
I take my little guy everywhere with me as well, I don't fly much though( can't stand planes! ) Good luck in whatever you decide!