Changing default values on the model with Mongoose

Let's say I'm implementing the logic for a factory that produces airplanes. I have some schema which corresponds to a generic type airplane. But specific types of airplanes are implemented as different types of models. Different types of planes need different fuel tank sizes, so default values should be specified in the logic for their model somehow.

For example:

airplane.js:

var mongoose = require('mongoose')
, airplane = new mongoose.Schema({
  fuelSize: {
    type: 'Number',
    default: 500
  }
});

module.exports = airplane;

boeing.js:

var mongoose = require('mongoose')
, airplaneSchema = require('./airplane');

/* Somehow change the logic of airplane schema to have a different default value
  for fuelSize */

var Boeing = mongoose.model('Boeing', fixedSchema);

module.exports = Boeing;

Obviously, I could console.log the airplane schema and find the right property to change, but is there any elegant, non-hack way of doing this? For instance, something like

var Boeing = mongoose.model('Boeing', airplaneSchema, {/* Somehow specify the fixed default value here */});