There is no translation for Air on crowdin.net.
It is used in the superflat customization for air layers so it should have a translation too.
Linked issues
relates to 2
Comments 18

See also [MC-1352]

Is this still a concern in the latest Minecraft version 14w08a? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Yes
Still a concern in 1.7.5 and 14w10c
Confirmed for 1.8.9 and 15w51b.
@@unknown: I don't want to discourage you from testing but it's rarely necessary to confirm tickets on stable releases if the (later) development releases are affected as well.

The translation name is createWorld.customize.flat.air=Air
however as tile.air.name
is missing (is returned when using the /testforblock
command) it might make more sense to use this instead
Confirmed for 16w02a.
it's fixed in 16w02a, for the CanDestroy/testforblock issue, see MC-64455
i confirm it