I am obviously into much smaller planes than our friend ananas ;-)
My ubecs are only 3 and 5 amps.
Not long ago people were competing in F3A class with fast .60-engine pattern planes and used small NiCd batteries like in the picture. 600 mAh would last more than one 10 minute flight. The new 2000 mAh NiMh batteries last "forever" before any need of charging. We are naturally talking different when coming up to big scale models with engines of 100 cc and up.
I had to check the amp draw from a few of my servos:
20 gram servo – stalled 0,5A
50 gram digital servo 1,0 A
I guess that the more normal 10 gram servos used many of in the modern planes will stall at about 0,25 A.
The “normal” draw from the servos are obviously a lot less than the stalled sevo.