The issue of elevation in game play has been a conundrum from the start of miniature war gaming on through to current times in role playing. Every method from stacking dice, using string to hang figures from lamps, to stacking smaller tables on top of the game table, and writing elevation on small pieces of paper have been tried.
Plenty of companies have produced gadgets to help deal with the problem in more elegant ways than notes, string, furniture, and dice stacking.
Among the more interesting are Dr. Wizard's Patented Elevation Indicator, an acrylic cylinder marked with numbers and multipliers. Bands are placed around it at the numbers indicating how high the figure on top of the cylinder is at present. Reviews seem to indicate that the Indicator only comes with a single band to mark the elevation and additional bands can be purchased. Reviews also mention that the bands slide around too easily on the cylinder. Another obvious drawback is, what do you do if another figure has to be directly under it?
Another option is from Litko, they produce a number of game enhancement items including invisible character and monster stands, torch stands, and their flight stands. I have all of these, yet have not used them for one primary reason. I have not put in the effort to locate a glue that will dry clear and stay clear, and I'm picky about yellowed glue on clear plastic. My secondary reason is working out safe storage to keep them from breaking once assembled. I plan to eventually use the flight stands in combination with the Combat Tier by Tinkered Tactics.
I own two of the Combat Tier Family Packs, because during my move I initially misplaced the first set.
These are sturdy acrylic stands that can be adjusted to provide various elevations. They are clear allowing players to see through to what is around the figure. They also fairly strong, but I won't be putting anything breakable on them that could fall or topple the tier. No finely painted metal minis or resin figurines, plastic minis only. I might try putting some dwarvenite terrain higher up to represent flying dungeon locations.
Take a look at the pictures below. These will give you some idea of how useful they can be, and should provoke the imagination for other ways to play with the combat tier. The pictures below show just one set.