Pants.
I don't even see why this is a discussion.
She would wear the same suit that Kal-El, Faora, Zod, and every other Kryptonian wore.
This I pretty much agree with. Though personally I would probably change the "main" color of the suit itself from blue to more of a brighter silver/platinum color, depending on how it would translate (for lack of white, which I don't know would mix all that well with the chainmail styling)
is supergirl going to be in Superman / Batman movie ?
It's rumored that either Kara or Wonder Woman will be in it
I don't even see why this is a discussion.
She would wear the same suit that Kal-El, Faora, Zod, and every other Kryptonian wore.
Kara would stop wearing the kryptonian suits after she start living on earth and start to wear her Supergirl suits. Like the cheerleader skirt and maybe her new 52 one. The way Iron Man has more than one armour.
The version Helen Slater wore in the 1984 movie never looked remotely like a porn parody. I thought it was a fabulous costume and combines the most classic elements, even though it's actually the Matrix Supergirl who wears that costume. I prefer it to the bare midriff version.
Helen Slater's costume looked completely dignified and not demeaning whatsoever. I definitely don't want Supergirl to be wearing pants.
This. My favourite version of the costume bar none:
It just wouldn't be Supergirl without the skirt.
I really hope they actually do a proper origin story where she meets Superman like in the comics if they ever put her in the new films.