Courtney and WEBF have it right. It's all about global projection of military power and layered defence. Ships at sea are vulnerable to attack and 'proper' fighters are the key to long range air defence. This isn't a pissing contest, it's just the way it is. Maybe that's why F-18 was so successful. We need both roles from our organic air, sadly Harrier couldn't quite do it. But it was bloody good at what it did. Sad to see it go.