There is excellent evidence that driving while under the influence of alcohol is a major contributor for road acccidents and deaths.
Random and on-suspicion breath testing is a proven deterrent and thus justified.
There is no evidence that flying while under the influence of alcohol has been a contributor to commercial accidents and deaths.
There is thus no rationale for random or on-suspicion breath testing.
QED I would have thought.....
PS: There is excellent (incontrovertible) evidence that flying while fatigued is a major contributor to commercial accidents and deaths.
Therefore there is an excellent rationale for mandatory fatigue testing.