There is no logical reason why the Army couldn’t absorb the airfield security task. That doesn’t necessarily make it a good idea.
The Army - in the era of Carter's "time of Commando plenty" - tried to take one of the RM's specialist tasks off them. The lead SO1 (who I know), made an assessment it'd take at least three Battalions (vs. the RM's one), and that it would a) likely be chinned off to a County Regiment and they'd all hate it and b) they'd struggle with a lot of the training required. The idea was quietly shelved, and the RM Commando continues to complete the task.