Turning something you love to do, into a job, many time pushes the love of the activity out the door and simply converts it to a job. My recommendation would be to at least build the airplanes YOU want to build and then sell them after their done. Taking orders from people somehow lets them steer the project and they will turn themselves into genuine pains in the __! If you were going to do this as a business, then yes, you have to let the customer have it his way. However, if you do it as an artist, then you are in control! Since there is no money in this idea, why would you let them give you any grief? If it will be for fun, then by all means, have at it!