Will this app work on the iPod touch or the iPhone? I'm hoping you say yes because I just bought it thinking it did, and I don't own an iPad and probably won't for a while.

Afraid not :( ...the iPhone is too small to have a full MCDU keyboard plus screen and R/L K's

It could potentially be made to work with the iPhone 6+ but the problem is that making it for one iPhone requires making it for all, including the still existing iPhone4S which has an even smaller screen than current iPods and iPhones.