Over done acrylic

What brand of acrylic?

Regardless of the brand, I think you're looking at a repaint, especially if it's acrylic over acrylic. If it's over an enamel base, you might be able to salvage the base color by using alcohol swabs to gently remove the acrylic. No guarantees that you won't just smear the base even more.

Thanks for the replies..it's Model Master acrylic over acrylic. And it may/probably will have to chasnge its' colors to Manfreds plane!

Rather than paint over, you could strip it and try again. While I rarely use MM acrylics, those I've used secumb to a mixture of one part Simple Green, one part Windex, and two parts water. (Someone here posted that formula, but I've forgotten who.)