Skyhook
Ian,
The Sea Harrier has indeed got anti-gravity devices ( not paint of Area 51 UFO technology, still trying to prise that out of the secret lab's at Dulux & the USAF ).
However there are two highly hushed up things I probably shouldn't be mentioning here;
one's called light weight, especially if compared to the other Naval aircraft you mention.
The other's called Pegasus with vectored thrust!