How to explain mileage running to family and friends and coworkers?

Since I started mileage running this year, some people look at me like I have three eyes when I tell them what I'm doing this weekend or that I'm going to Panama X times in X months. I don't really care what acquaintances think, and friends just shake their head but they knew I traveled a lot anyway even before I started running so they at least understand kind of why I do it.

But recently my new boss asked me what I'm doing the 4th of July holiday weekend and I told him I'm making a quick trip to Panama (I forgot I told him that I was in Panama a month ago) and he asked why I'm going again. So I told him I'm doing it to get miles. He seemed interested and I explained it to him but some coworker friends (in a different group) later told me that he may think I have too much time and money on my hands or subconsciously think in his mind that I'm always on vacation (even though I'm not taking vacation on most of the trips).

I think they do have a point so I'll be more careful about sharing my hobby and all my premium cabin flying in the workplace.

If you take mileage runs, how do you explain your hobby to those around you? Or maybe you don't even mention it. I don't like to lie but I guess I could have just answered my boss that I'll be just hanging around this weekend. Not mentioning that I'll be hanging around in planes and airports.