Given what you have in your signature the 18-55 could be ok for fireworks depending upon your placement from them. Let the camera do some of the work for exposure. I always have shot these in AV to have a reasonalbe depth of field, 5.6 give or take and then you end up with a somewhat longer shutter speed (a tripod is a must when shooting these). Check your display and histogram for the first couple and then you are good.
For airshows, I would suggest that you need something around 400mm. Your current lens is not going to do it. I've done some aircraft with my 100-400 and it works very well. A 70-200 with a 1.4 might get you by.