heheh, cute animation. Might be cool to give one of the people a mouth that alternates between the current frame there, and a new one where the bottom and top lip are extended a pixel. I think It'd give the expressions a little variety.
Like this:
frame1:
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frame2:
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The darkest shade on the steering wheel is also a little hard to make out from the shirt of cat, would look better if it were lighter.
Other than that, great job.