I'm making a few of assumptions:
a) You are "aircrew."
b) You live in England
c) You feel guilty about "calling in sick."
If all three are correct, you could contact your GP and ask for an "amended duties" medical certificate.
He may write something along the lines of "fit to work but to avoid air travel," or something similar.
This could satisfy all corners- you're willing to work, your nasty GP has said that you can't fly, and your firm's absence figures keep tip top.
It's up to your employer to find you wor during this period, they may well send you home if nothing suits :-) At least you've done your bit.