Traveling with a new baby is always a tricky proposition. In my perfect world, you would wait until 2 weeks after the “2 month” immunizations before you travel on a plane. It is important to note that you can receive the “2 month” vaccines as early as 6 weeks and then fly as early as 8 weeks.
The reason for this is twofold.
First, young infant’s immune systems are still developing during these early months so they are more susceptible to infections.
Second, infants through 2 months who develop a fever are often subject to a significant inpatient work-up.
This is particularly true if they have not been vaccinated. There are emergencies that require travel before 2 months and, if this is the case, I think it is okay to go. You should check with the airline to see if they have an age minimum.
Regardless of when you travel, always make sure you are the first folks on the plane and the last folks off the plane. The aisles can get pretty chaotic when everyone is getting on and off. Also, I recommend researching a health care facility at your destination just in case.
Remember, your pediatrician is available 24/7 by phone no matter where you are. So, if the need arises, I recommend calling your pediatrician as your first step.