Tethered Aerial Release Developed In Style
From Tardis Wiki, the free Doctor Who reference
This TARDIS, unlike it's namesake, was a hot-air balloon, created for Jackson Lake while he was under the impression that he was The Doctor. The name was an acronym for "Tethered Aerial Release Developed In Style."
It was piloted by the Tenth Doctor,and was key in the destruction of the CyberKing.
The balloon was described by Jackson Lake as being powered by gas(most probably hydrogen),yet when piloted by The Doctor,it was powered by only hot air.