Beautiful work. I love the background. Its just perfect.
I am not a big fan of this suit though. Not your fault of course, DC has made it rather gaudy lately. I prefer the cuter version (both suit and haircut) of the 60ies Supergirl from your "Rise of the Supergirls". I like this haircut as well, just not the suit. Perhaps you could treat us with some 60ies Supergirl in the future (you can always blow some wind and lift her long skirt to make her sexy).
Also, this pic of Supergirl flying reminds me of that famous pic of PowerGirl flying from Adam Hughes. I know you 'll love it!