those sound like TX battery packs, and probably aren't very high in C rating. They will probably get very hot and not last long in a plane..

the same place builds nice packs with their own cells. Go to the "custom packs" section and build a brick pack with 2/3 CBP1100 cells... the 2/3A packs aren't large capacity MAH packs but they are as good as your gonna get without spending lipo money...

before I went to lipo I was getting 8, 9, and 10 cell brick packs from them.. good batteries, good service..