Queen Sheryl #1 obviously.
However, my #2 spot changed after the Ranka supermove in episode 11:
Even though I don't normally like moe/loli characters, the sheer humor and absurdity of that event won me over. If we're voting for Saimoe, I'd definitely vote for Ranka as number 1.
And Alto-hime goes from #2 to #3 since you can't have a triangle without the main male lead... and he's actually a fairly competent pilot.