Stacking bead boxes like these:
http://www.amazon.com/Stackable-Acce.../dp/B00UXZT95Y

They don't work for titans or some larger flyers, but you can fit 5-6 infantry strips or four tanks in one compartment.

This one doesn't stack but it's quieter to open and close. I like it more for BFG ships:
http://www.amazon.com/Jewelers-Stora.../dp/B000OVOKTC