Unless you plan on purchasing one of the umbrella strollers that are suggested for ages from birth on up, then I'd say no. The only umbrella strollers I know of that are approved for those ages are the Maclarren, Peg Perego Pliko and the Combi Travel Savvy. Now, these are all VERY expensive strollers $200 and up, and I recommend them highly, I've owned all three of them (well the Combi in a double). Any cheaper umbrella stroller isn't going to be supportive enough for such a small baby, let alone fully recline if the baby falls asleep. Bringing the stroller on the plane, won't be a problem with either type, since you can't bring either on the plane. You must leave them folded up outside the door in the jetway. Yes, carrying the stroller on/off the bus is a pain, but if you're with someone else, they can carry the stroller, and you can carry the baby or vice/versa. I've been to WDW with MANY types of strollers over the years, and to be honest carrying ANY stroller is a pain, some are just heavier than others. I'd bring the one your child is most comfortable and used to at this age, since at 4 months they can be VERY particular!!!!