Personally I think that the air pressure change on the air planes and the 
noise/environment would be more stressfull for the birds. If I were you, I 
would bur two small pet carriers. The plastic ones used for cats and tiny 
dogs. I would screw a perch from side to side securely about two inches off 
the ground. Place heavy plastic dish with food in one of the corners away 
from the pirch. Also give the a fruit like an apple to replace the water dish 
and eliminate water spilling all over. Even if the trip takes twelve hours, 
the birds will surely be ok. Just make sure that they dont get hit
by 55 mph winds whenever you open a window. They don't fly that fast.
Ooops...I meant "buy two small pet carriers." One for each bird.  
 
---
---------------