Well, to make a quick trip with just me and DH, I honestly would fly. And I say this as a strong proponent of driving! If DH and I had a whole week, not sure what we would do--depends on airfare.
We leave from the Mpls airport and in order to get nonstop, we'd have to fly Northwest which is not exactly famous around here for good airfare. (one trip we did contemplate driving to Des Moines and flying Northwest into Mpls and then down to Orlando cause it was going to cost about $160 less to do it that way, but the idea of then driving home from Des Moines did us in!) So it's an hour drive to the airport, another 1.5 to park,check in, go through security and wait for the flight. If we couldn't swing the $300 airfare then we have to allow time for a layove and switch planes etc. If it's just us as I said, then it is a toss up.
If the kids come it's a whole new ballgame. Three kids brings that airfare to $1500. Then factor in hauling carseats, stroller, diaper bag, backpacks, blankies etc through two airports, feeding the little monsters, changing diapers in an airplane bathroom, layovers where they won't get your darn stroller off of the plane for FOUR hours....give me my own car anyday of the week! DH and I are trying to figure out how to convince his dad that we (the 5 of us) could just drive down and meet the rest of the family in FL when we all go on a big family trip next year. I am already dreading the flight!