M.B.
My daughter lives in South Korea, in Seoul.... I'll ask her when she gets up. (She is home visiting for the summer.)
Basically, I believe on international flights you get two checked bags at no charge...
If your hubby is military, you should be able to get the food and formula on base. I know my daughter buys a lot of stuff at Costco in Seoul... she isn't military, though.
Ask hubby to check out the PX.... have him look specifically for the formula brand you use... it should be available, unless you use something different.
Also, you can get the small hand food grinder to make baby food.... take that along, and just feed him what you eat (within reason, anyway). My daughter says that Korean babies, once they start eating, just eat what mommy eats! She will check with a few friends that have raised little ones over there, also.