Edit in JSFiddle

/**
 * @constructor
 *
 * @param {String} name
 * @param {String} type One of Vehicle.TYPE_*.
 */
var Vehicle = function(name, type) {
  this.name = name;
  this.type = type;
  this.error = null;
};
Vehicle.TYPE_CAR = 'car';
Vehicle.TYPE_MOTORCYCLE = 'motorcycle';
Vehicle.displayTypes = {};
Vehicle.displayTypes[Vehicle.TYPE_CAR] = 'Car';
Vehicle.displayTypes[Vehicle.TYPE_MOTORCYCLE] = 'Motorcycle';

/**
 * @return {String}
 */
Vehicle.prototype.getDisplayType = function() {
  return Vehicle.displayTypes[this.type];
};

/**
 * @return {Vehicle} A clone of this vehicle.
 */
Vehicle.prototype.clone = function() {
  return angular.extend(new Vehicle(), this);
};

/**
 * @return {Boolean} TRUE if this vehicle's data is valid, FALSE if not.
 *                   If FALSE, this.error is populated with a message.
 */
Vehicle.prototype.validate = function() {
  var valid = true;
  this.error = null;
  
  if(this.name === '') {
    valid = false;
    this.error = 'Vehicle name required.';
  }
  
  return valid;
};

/**
 * @constructor
 */
var GarageCtrl = function($scope) {
  $scope.vehicles = [
    new Vehicle('2011 Nissan Frontier', Vehicle.TYPE_CAR),
    new Vehicle('2007 Honda CRF450R', Vehicle.TYPE_MOTORCYCLE)
  ];

  // Expose Vehicle class to scope and initialize the new vehicle
  $scope.Vehicle = Vehicle;
  $scope.newVehicle = new Vehicle('', Vehicle.TYPE_CAR);

  /**
   * @param {Vehicle} Vehicle Vehicle to delete.
   */
  $scope.deleteVehicle = function(vehicle) {
    for(var i=0; i<$scope.vehicles.length; ++i) {
      if($scope.vehicles[i] === vehicle) {
        $scope.vehicles.splice(i, 1);
        break;
      }
    }
  };

  /**
   * @param {Vehicle|Object} newVehicle Vehicle to add, or generic object castable to a Vehicle.
   */
  $scope.addVehicle = function(newVehicle) {
    newVehicle instanceof Vehicle || (newVehicle = angular.extend(new Vehicle(), newVehicle));
    
    if(!newVehicle.validate()) {
      alert(newVehicle.error);
    }
    // Input OK
    else {
      // Clone it onto our set
      $scope.vehicles.push(newVehicle.clone());
    }
  };
};

<div ng-app ng-controller="GarageCtrl">
  <h1>My Garage</h1>
  <ul>
    <li ng-repeat="vehicle in vehicles">
      <strong>{{vehicle.getDisplayType()}}</strong>
      - <span>{{vehicle.name}}</span>
      - <a class="deleteBtn" href="" ng-click="deleteVehicle(vehicle)">delete</a>
    </li>
  </ul>
  <form ng-submit="addVehicle(newVehicle); newVehicle.name = ''">
    <select ng-model="newVehicle.type"
        ng-options="type as displayType for (type, displayType) in Vehicle.displayTypes"></select>
    <input type="text" ng-model="newVehicle.name" placeholder="Vehicle name" />
    <button type="submit">Add Vehicle</button>
  </form>
</div>