Actually a flight attendent is more at risk from a drunk and abusive passenger than any terrorist.
A few restraint techniques wouldn't hurt but most Aikido training is not that good a platform for that. On one hand you have dojos that teach so many variations they have kissed the KISS principle good bye and on the other hand you have dojos which are as direct and violent as anything taught anywhere. Teach a limited number of control techniques in the context of their current training. Just as the police do.