Why not floo instead of thestral to London?

[suehpfan]

No: HPFGUIDX 91646

snip
> Hitomi:
> Actually, I'm more annoyed that Harry never looked at what Sirius 
> gave him after Christmas.  If JKR had had him do so, there never 
> would have been a need to go into Umbridge's office, either time.  
> He just could have talked to Sirius through the mirrors, Kreacher 
> never could have tricked him, and Sirius would probably still be 
> alive.  It's always seemed to me to be a strange plot-hole 
> oversight. 
snip
> ~ Hitomi

I have always been troubled by this as well.  When Harry put the 
mirror away, he vowed never to use it and, evidentally, forgot all 
about it.  Why, when he broke it at the end did he throw it back in 
his trunk instead of in the trash?  Where is James's mirror, we know 
he had one.  I have a feeling the mirror (and perhaps all mirrors in 
the series) will reappear and Harry will be very glad he has it.  It 
is, of course, in several pieces now.  The better to share with 
others he needs to keep in touch with.

Sue