I have been traveling with my manual chair by air, train, ships and cars without too many problems. I even traveled alone from Texas to Canada a day after I received my chair!
I went to one of John Morris’ travel seminars at an abilities expo right before I got my chair. He uses a very heavy electric chair and he travels all over the world by himself. He has a helpful website.
Your husband should be able to bring his own chair. It probably is a good idea to contact the airlines just to ensure they have enough cargo space in the particular flights. I always make sure that I have enough transit time as I am always the last one to deplane.