Tasers can be a valuable tool, but they are too often being used as a the take-a-pill solution. I fear that preemptive tasering is replacing other important police skills.
In this case, the fact that the subject was in an airport makes the level of force used almost normal, rather than excessive, but they should have cuffed him immediately after the first tasering (yes, they would have had to pile on top of him, but they ended up doing that anyway) rather than tasering him again, and should have put a heart monitor on him immediately afterward.