Gas stoves are fine. Where you'll run into some possible issues is with the used gas cannisters. I didin't work for UA, but hazmat regs are set by DOT/FAA, and are pretty much the same across all US carriers. Last time I had any experience with this, as long as those gas cannisters have been completely purged, they are ok to take as checked luggage. Do NOT try and take any fuel. The airline's definition of purged and yours may differ. I have no clue how much these things cost, so please forgive me if I'm out of line...but I would probably buy a new cannister so there's no question. If the FAA Hazmat boys have been sniffing around at anytime recently, I can almost guarantee you that the airline folks on duty that day will err on the side of extreme caution.

The best thing to do is call United and ask. These regulations do change from time to time and it's always best to get the details before you get there when it comes to things like this. YMMV