D-Kfly (Space Fighter WIP) + Align / Orient Question

 From:  PaQ
3796.1 
Hello,

Here's a wip of a little space ship I'm actually buiding in my spare time.
Have to clean all the mess now :)





Btw maybe it's because of a lack of practice, but I can't find a way to realign / match the white surface exactly over the blue one (it's the same shape).
Anyone has a tip ?

EDITED: 4 Dec 2015 by PAQ