I am going to be traveling from TPA to SXM and will likely be flying either Delta or AA. I have Cystic Fibrosis, lung disease, and don't require oxygen or wheelchair assistance. What I do require is traveling w/ 2 carryon bags. One is a "personal bag with computer, nebulizers, etc.." and 1 is a medical device that I can't lose. I don't use it on the plane but it costs thousands and thousands of dollars and medically would be screwed from a health perspective if it were lost.

How do I get the airlines to allow 2 carryon bags with me?