can't make more water wings

“M-Misaka-san...!?”
Saten looked over to Mikoto with a look in her eyes like she was relying on her, but
Mikoto shook her head.
“I can’t. In order to make those wings, I used the water molecules floating in the air, but
that has reached its limit. It was crucial that they were distributed with a certain
proportion, but the molecules have gathered together with time making them nothing
more than drops of water. Simply put, I can’t fly. And since Kuroko is down, we can’t use
her teleportation either.”

- Toaru Kagaku no Railgun SS1, Chapter 8