I'll be brave. I started off with a fixed salary, it was ridiculous and amounted to around $9.50/hr (which 17 years ago was a serious pay cut). We petitioned the powers-that-be and got it changed to a competitive hourly rate. But we had to do a regional survey to find out average pay for flight RNs/EMT-Ps.
The thing that really sucks about either choice is that the management knows they "got you" because we love to fly. I had a manager who literally brandished incoming applications as a threat ("here's a list of people who will do your job for less money"). big question about salary is: pay for 12/24 hr shifts, so what about all the education days and PR events? how does that figure in? I ended up being paid hourly for 40hrs/week but only worked 36, the catch was if we had a late flight or educational day it wasn't factored in, my manager said "it all evens out in the end"....which is probably true.
Good luck and stay safe!