OK, I'll start off....
I'll assume batteries are contained in a separate box (like the ammo can I use for battery transport), as is your radio equipment. Also assuming that you are flying FT-style foam-board models.
That said, here are the contents of my box:
Packing tape
Propellers (lots of propellers)
Spare prop-saver rubber gaskets (if using them, of course)
Rubber bands (for wing hold-downs)
Appropriate tools:
- Allen (hex) wrenches for adjusting linkage stoppers
- Other wrenches as needed for changing props
- Several sizes of phillips and flathead screwdrivers
- Razor knife
- Glue for field repairs
Trainer cable for your transmitter? (you never know when you might have the opportunity to use it)
Additional stickers (with contact info, AMA#, FAA#) to place in the airplane if one falls out
Your FAA registration certificate (sad that we need that, but....)
If flying multi-rotors:
- MANY more propellers
- Spare screws and other appropriate hardware
- Spare booms
- Spare tail servo if flying a tri-copter
- Add a few more props
Other add-ons will vary if you are flying balsa models, or using FPV.