The whites on the car are too bright in comparison to the rest of the image, hurting the illusion.
You can try lowering the brightness of them slightly with the Burn Tool, or Image>Adjustments>Selective Color>Whites, increasing the black slider at the bottom.

You might also consider lightening the background image, as it seems very dim and dark, which compounds the too light child and car image.

Creative idea to have the gondola relate amusingly to the hot-air balloon.

MossyB has highlighted how the balloon and gondola don't properly relate visually as a consistent whole, so I'll just focus on the balloon itself.

The balloon should be opaque so background clouds don't shine through. 'Giant pelican roosting on a traditional, boring-brown hot-air balloon' doesn't quite seem consistent with the theme objective. Maybe the traditional-hot-air-balloon portion could be replaced with a hot-air-balloon pelican's nest.

the clouds are not shining throu the baloon is pasing throu the clouds and the balloon is made frome the pelican so i think its on theme