Thank you to your husband for his service!
It sounds like your family really has everything you need. It is amazing how little babies need at this age...and how much more you are likely to come back with. Just include a special blanket or toy that your son is familiar with. Pack a lightweight duffle bag to catch the overflow on the way back...trust me, there is always overflow.
A couple of practical matters:
get a full copy of his medical records
birth certificate
his social security card (if you've received it)
I've been travelling with my daughter since she was the same age. Here is my survival kit...it isn't as much as it seems once you've packed it all. For the plane:
If you're not breastfeeding, use the premix liquid formula or premake bottles and use a cooler bag and cold packs (just notify TSA before you go through security and they will let you know how to declare it).
Pack twice as many diapers and wipes as you think you'll need.
An extra shirt (or two) for yourself and clothes for the baby (two pieces for easier diaper changes and clean-ups).
A few small garbage or (hole-free) grocery bags.
Use a small bag inside of a larger carry-on...this smaller bag can carry one or two diapers, a garbage bag, a pacifier, one bottle. Something that is very easy to handle and carry to the bathroom if needed. The larger bag can be packed away and you don't have to dig through it until you actually need you back-up supplies.
Changing pad--use a small absorbent one like you would use in a crib (accidents and messes can get away from you on a waterproof pad).
If you can afford it, buying a seat for your son will give you some extra room to maneuver (and a place to change his diaper). Not all planes have changing tables and you can end up being confined to your seat the whole flight.
Snack for yourself.
If you use a sling or Moby wrap...they can be indispensable in keeping your hands free during all parts of the travel...and you can nap on the flight without worrying about dropping your little one.