Technically..
They aren't Air Craft Carriers. Or at least they weren't originally classified as such. They have no real attack capability. Back in the late 60s the Brit Government made a decision to not have real attack carriers. They had an excellent design for a new Ark Royal Class but cost was prohibitive. In fact parliament made a law prohibiting the procurement of air craft carriers. They scrapped the two carriers they had in existence at the time (Ark Royal and Eagle were there names I think). They shelved plans for the Malta class, which was to include a new Ark Royal.
The Brit Navy, which had already undergone an Air gutting pre WW2 and realized the dangers of not having a Fleet Air Arm came up with a decent way to get at least some air capability, if only for loval fleet defense. They came up with the concept of the Sea Control Command Cruiser. Technically if you look at the history of the Invincible, Illustrious, and Ark Royal they were built as Sea Control Cruisers with local air defense capability. They've never been officially rated as Air craft Carriers. The Harrier isn't known for her range, or her strike capability, but is a decent support Air Plane. Before the Falklands war the Brit Navy was going to sell one of these to the Aussies. I believe it was the Invincible. The funny thing is the reason they were gonna do this had nothing to do with finances or anything like that. They were gonna sell her so Parliament wouldn't catch on that in fact the Brit Navy considered these ships as Air Craft carriers. The reason being to have a viable carrier force you need 3 carriers. Navies obey the law of threes. They figured in a pinch the Aussies would lend her back.
Then came the Falklands and the Invincibles pretty much proved their worth for local defense, and also proved they sucked as strike carriers.
All in all interesting ships, and quite successful (albeit ugly) ones.
As for REAL Carriers. They only use the first 200 feet to take off. Which is less than the Brits use on the Invincibles. the rest is used for refueling and landing operations. Harriers rarely "jump" off the Invincibles because the jump severely limits their range. They have no catapults (otherwise they'd have to call them Air Craft Carriers) so the solution was to put the ski jump so Harriers could take off without jumping. AND given the choice between going into battle in an F14/18 and a Harrier I KNOW which one I'd choose.
Tron