No we can't hope to everything we once did. But there is a level of capability we should be able to provide. We have restructured our forces to fight expititionary warfare like we did in the 1930's and look what happened when they went to war without proper aircover!!
As to Dip clearences they can have caveats like no offensive air. Again you are relying on somone elses good will and at some point in the future we may be having to send a force into an area which there is limited of no goodwill for us. BTW I said a Falklands type operation IE proper unilateral expiditionary warfare and force projection from the sea. Which is more viable than dropping an airborne Brigade in which even 16 AA admit is a non starter which is why they focus on dropping a Batalion group and TALO or Air Assualt the rest in.