Basically here's how I set up my scanner based on the assumption that I have only one scanner to use for all listening.
One bank has off-field public safety. Usually just police; everyone from staties to locals. I listen to this bank as I drive in to be alerted to traffic tie-ups, etc. Plan on arriving as soon as the gates are open. Arriving more than one hour after the gates open = sitting in huge traffic jams and missing a good portion of the show.
Another bank has on-field public safety. Again, usually just police, sometimes commanders nets, etc if available and known to me. Also I'll enter low-power tactical freqs. used by civilian law enforcement if I know them or can find them ahead of time. If it's a military show, I'll also put ground support freqs in this bank such as flight line, etc. but you may want to break ground support freqs out into its own bank.
These two usually get locked out once I'm on the tarmack.
One bank for local ATC. I'll hunt or signal stalk for the air boss as soon as I arrive at the show and enter that freq. or those freqs into the ATC bank. I'll lock and unlock this bank as I wish during the show. Also, I may lockout certain freqs. in the ATC bank during the show so I can monitor most closely others. For instance, I may lock out departure while listening to tower, ground and approach. Sometimes if there's going to be a fly-by by a B-2, I'll also have the freq for the center that covers the field as well so I can be alerted to when the aircraft arrives in the area.
One bank for air-to-air freqs. used by performers. Freqs. like 123.15, 136.675, 376.025, etc. You might want to duplicate the air boss freqs here as well.
One bank for the featured performer (Blue Angels, T-birds, etc.) Usually, I'll put no delay on these freqs. When the featured performer flies, I lock out everything else.
Basically, think of the various situations you'll want to monitor as you approach the show, during the show and departing the show. My experience has been if I only have one receiver I can't listen to everything because there's just too much radio traffic at an airshow plus all the ambient sounds, conversations with others, eating (right, Ken?) etc. By using multiple banks, I focus on what I'm most interested in at any given time.
As you can tell, successful monitoring at an airshow involves lots and lots of research prior to setting foot on base. I know I won't be able to hear everything but if I can hear 80% of what's going on, I'm happy. (The old 80/20 rule. It's just a hobby, isn't it?)
And definitely definitely bring your headphones!
Enjoy and happy listening.