Float freely up in the air (5)
I believe the answer is:
'up in the air' is the definition.
(aloft means above or overhead)
'float freely' is the wordplay.
'freely' indicates an anagram.
'float' is an anagram of 'ALOFT'.
(Other definitions for aloft that I've seen before include "Animistic cult" , "In the air, overhead" , "In the rigging, up high" , "up the mast" , "At a considerable height" .)