These days we are working on a feature that should bring more depth to Altitude0 - plane customizations.
I would prefer if this update was already good enough to just release it, but it will have to wait for a bit longer so that it's fully ready.
Instead here's some info on how this feature will work.
Customizations will be roughly split in 2 groups: performance adjustments and cosmetics.
Performance Customizations
Performance can be adjusted by attaching / detaching a bunch of parts from the plane. These parts will be unique to each plane and will be collected after races, usually as a reward for good results.
We split them into body tunes and engine tunes.
Body tunes affect mostly aerodynamics and weight of the plane. Extra wing spoilers, different ailerons, elevators, propellers to name some. Each comes with pros and cons. Some part could reduce drag but at the same time make a plane less agile. The idea is not to make a perfect plane by attaching all the best parts but rather to find your favorite settings for a bit of extra speed and most importantly - have geeky fun by testing different combos.
Engine tunes are parts like different engines, extra exhaust pipes, different air intake and boost adjustments. Again, goal is not to be realistic but rather have fun with tweaking.
Cosmetics
Cosmetics on the other hand were added to allow visual adjustments to planes. Skins have already been around for some time, new thing coming are stickers. Sometimes special skins and stickers will be given for racing during special events (time limited) and as a recognition token to players who play Altitude0. We will be adding new ones with time to keep the game fresh.
Other cosmetic items will be colored smoke, colored wing markers and different night light reflectors.
We'll see where this goes - imagine Batman sign projected when flying night races. 
We are still working on item presentation but here's a screenshot of a new 'My Corner' interface:
My Corner (call it hangar or garage) section will certainly become more important with customization update.
Some tuning will most likely be unrealistic or exaggerated but it will hopefully add more fun and extra dimension to the game.