Is there going to be a 4th book to the Airborn series by Kenneth Oppel?

There has to be Matt and Kate got engaged duh

''I love Matt and Kate and would hate to say good-bye to them forever. But Starclimber does leave them at a very interesting point in their lives... I might return to them, but first I have several other stories I'm going to tell first...''

I found the above quote from Kennith Oppel online at http://kennethoppel.blogspot.com/2009/08/august-report.html