Q: What should you do if you have the flu but have to fly (say, to attend your sister's wedding)? Wear a mask? I think I might be coming down with swine flu (I was exposed at work) but my sister will never forgive me if I miss her wedding this weekend. A: If you're sick and have a trip coming up, go to the doctorespecially if you think you might have the flu (H1N1 or garden-variety). If the doctor says you have something contagious, you need to stay home. Period. As for masks, the CDC says they do not completely prevent flu transmission. So unfortunately, that's not a real solutionif you have the flu, you simply shouldn't fly. I know there are all sorts of excuses you can makea family obligation, a big meeting, "My ticket was expensive!"...