Make A List Of Flight Plans Loaded Into Program?

I'm trying to make a list of flight plans loaded into my program, with each flight plan having a list of waypoints along the route, along with a few other properties associated with the flight plan. Each waypoint has its own associated properties, i.e. waypoint ID, waypoint type, location, etc.

Here's the declarations:

Code:

Public Class WPinfo
Public WPType As String
Public WPID As String

[Code]...

How do I implement the List methods to access the list elements, and add, remove, etc? The way I'm doing it now just gets me an 'Object reference not set to an instance of an object' error during runtime.