Unique girl's name to go with siblings' names

Airen

Hi everyone! My husband and I are so stuck on picking a name for our 4th baby who could arrive any day. We already have:

Jett Sabre (3 yr old boy)

Aero Ciel

Echo Skye (20 month twincesses)

My husband is a pilot (and my name is Airen) and they all ended up with word names with an aviation connection. We didn't mean to make them such a theme, it just turned out that way with names we love. Now it is so hard to pick another that fits in the crew! I honestly feel as though we have exhausted all words/names in this genre so we are not stuck on aviation themed. But, I think some type of unique word name would fit best with the others. Any ideas are greatly appreciated. Perhaps something to do with the sky or to represent strength and/or the crazy journey she has been through already (complicated pregnancy from the beginning and now on hospital bedrest after my water broke at 28weeks until she arrives at 34 weeks at the latest)