Hi Ace,
First thing best of luck for your interview!!, the best thing you can do is find out a bit about the airport itself, eg watch system, number of appliances, type of appliances however I would not expect you to be asked many questions on this topic, it may also be an advantage to find out what duties the fire service carry out.
As to the appliances the main difference is size, airport appliances carry upto 12,000 lts of water and 1,200 lts of foam compared to 1800 lts of water and maybe 50 lts of foam, in addition to this we carry similiar rescue equipment to local authorities.
Aviation firefighting is a lot more "aggressive", due to the large amounts of kerosene aircraft carry, a lot of the job consists of training, equipment maintenance and testing then more training (maintaining competance!!), a lot of stations have a gym for when your not training!!, unfortunately A/C rarely come to grief at airports so the job can be a bit tedious, however its what you make it!!
Hope this has given you the information you require!!
P.S Airfields are catergorised by aircraft fuselage length and width, once again all the best!!