If I have to cancel a flight because of a personal sickness and I have a statement as such from my doctor, am I eligible to receive a refund? If not, how about a credit for another flight to a different location?
"Compassionate" isn't usually a word that comes to mind when thinking about the airlines these days. But in the case of illness, many airlines are more understanding than you might expect.
I checked with representatives from many of the major low-cost and legacy airlines, and nearly without exception, airlines will offer at minimum a credit for a future flight. If you can produce a doctor's note as evidence of a legitimate illness, some airlines will waive their change fees and/or offer you a full refund. Of course, with most policies, it varies on a case-by-case basis.
When faced with the prospect of canceling a trip due to illness, I suggest calling the airline and asking what it would be willing to do in your specific situation. Be sure to mention that you have a doctor's note. If you don't anticipate being medically able to fly in the near future, push for a refund, or for a credit that can be transferred to another person. After all, it never hurts to ask.