Bad is you may want to take TJ(and i understand) but i would not take him, as the other girls said. His health is fragile and there is always 1 person on the plane coughing.
With that being said, Travelocity is a good site, it has an option where you can book flight, hotel and car for a lower fare. I never did like cheaptickets And sometimes you can just buy your stuff separate and still come out paying the same amount if you bought a bundle package, you just have to look at them all and compare whats cheaper.
You can bring your car seat and stroller, normally once you get to the gait to get on plane they will check it in right there and give you a ticket to get it soon as you get off plane(dont check it in where you check your suitcases)
Diaper bag: You will need, diapers,wipes,baby food, and medication he may need, bibs, pacifier, a few toys, a blanket, 2 change of clothes(just in case) Then just pack more of the diapers etc in the suitcase(but have enough in diaper bag to last until you get to hotel.
When booking your flight it will have an option for kids and it ask there age, i belive under 2 can sit on parents lap free.
When planning this trip you need to think about the what if's also. Like, what if the NG tube comes out, do you have a hospital in mind you will go to, or if he becomes sick. If things like this happen you will not enjoy your time at the wedding, those are just a few things to think about really hard.
There are lots of germs so to be on the safe side for you guys i would just leave him home.. also its harder to breathe on a plane... so if he has had trouble breathing thats another reason i would not take him.. its better to be on the safe side
personally with all of the compliations with TJ I would not want to take him on an airplane because of all the germs on a plane. So if your mom is willing to care for him I would take her up on it, you and your husabnd deserve a break anyways, plus if he caught the flu becasue someone a few rows away was sick, you would feel horrible. But that's just my opinion