We flew with my twins from one coast to the other when they turned almost 2, so consider it's a plus that you're not going as far. Definitely purchase a middle seat between you and your husband. You'll need the room. My two would not sleep and needed to be up and about constantly. We purchased small doodle pads and toys that we didn't show them beforehand, so they were new and intriguing during the flight. Have a fresh stash on the return flight. If you have a smart phone that has kids apps (like the iPhone), get some free and inexpensive toddler games (that was a big hit). Bring plenty of snacks and books too. I will say that our trip was exhausting and it required both my husband and I to be in it fully. So you may need to have a talk with your husband that it will be a lot of work and he should prepare himself. Getting books from the library about airplanes for toddlers is very helpful so I suggest having your husband read some of those to his girls. The more you can do to prepare everyone, including yourself, mentally, and to not have great expectations that everything will go smoothly is key. When it goes ok, it feels like a triumph.
Also, it was hard work to get everyone and everything (diaper bag, stroller, kids with shoes off, etc.) through security. There are restrictions, I think, still in place about the amount of liquids you can bring on a flight, such as Purell. So I made sure to pack essentials, pack lightly, and got the kids some easy-to-pull-off shoes. I also confirmed with the airline about where I could leave our stroller and most will allow you drop it off right when you enter the plane. It should be waiting for you on arrival as soon as you exit the plane.
Tell your husband: suck it up and to go with the flow. Having twins is a lot of work but is rewarding and special. Good luck to you!