Do ER , don't waste your time on a télé or med/surg floor.
I don't know a lot about Flight nursing but I have chatted with a flight nurse a while back. She told me I needed to do 5yrs of ICU to be even considered.
To become a flight nurse, you need to build your critical thinking skills, I think that is better developed in the ICU. But if you cannot find ICU positions (please do not stop looking), I would even move somewhere just to get ICU, out of state. Just don't give up. Also, ER experience is also good because you develop skills on how to act in code situations.
Don't doubt yourself. I know you may feel that way right now but don't.
At my hospital, once you are in the ER, they cross train you to go to ICU. Find places that do that. Do not limit yourself.
If this is truly what you want, fight for it and you will get it. Gluck!