I am surprised the axis haven't been able to move it so far. That triple base isn't the only air field on the front line.
Eh, that's mostly because we don't try. There are very few axis pilots that get excited over capture the flag; lots of allied squads seem to love it.
Personally, I find the base capture system in AH to be an insignificant improvement over what HT/Pyro implemented in warbirds ~15 years ago; the same basic idea remains. Part of what attracts me to the AvA is that bases
don't frequently change hands, so I don't have to search the map to find a new fight and don't see so much of the seal-clubbing that goes along with base capture efforts.