Buddy of mine used to always toss side business ideas around. Well, actually, he threw me ideas and I shot them down usually.

But the conclusion I usually came to was that nothing would pay as much as just picking up an extra airline trip. For me, I could do all the ground work, learn a new skill, or figure out how to start and run a business, take risk, or just grab a trip in open time and make the money that way. I had a hard time finding something that seemed to have a cost/benefit analysis beat just flying 1 more trip.

Obviously owning a thriving business can have tax benefits and possibly be sold for a big profit later on, but there's real risk in starting a business. The statistics on starting a business are not confidence inspiring.