Yes, make it an event like bettyeanne does, when Yoda's carrier comes out, Yoda jumps right in, because he knows he gets to go somewhere fun! He's a outdoorsy busy boy and always wants to go with us everywhere! But once in the car, he gets a little fussy and wants OUT of his carrier!
Raiza: perhaps start by giving Cosita a treat when she gets in the carrier, then take her for a short stroll outside or something. Once they get the association down of treat or outside (after getting into the carrier or purse), they'll be happy to do it every time!