I wouldn't fly with a baby that young. I flew with my son at 4 months and that was hard enough (on both of us)! Just my opinion though... YMMV. Some infants do fine in the car, others appear to become temporarily posessed by demons. Garrett has brouhgt up a an excellent point about changing and (if noone rides in the back with the baby) feeding. Prepare to stop a lot more than usual. Doubling travel may be a bit of an exxageration but it will certainly take a lot longer. We fed our kid plenty in the the car in his car seat. He was on half breast milk and half formula and we often gave him bottled breast milk or formula in the car. My son had no problems eating in the car seat but then he still has no problems eating so again YMMV. Don't sweat it. Don't rush. Enjoy the trip and your new addition to the family. Making the trip take twice as long may not actually be that bad of an idea.