The Eurofighter would probably have been a more succesfull aircraft with a better air to ground capacity from start even if the plane would not have been ready earlier due to the more protacted negociations and discussions. Carrier borne version would have been developped and might very well have led to the design of larger italian, spanish and british carriers, maybe even a common design with the french, possibly based upon a revised, non nuclear De Gaulle design.
The common plane design would also be stronger for export. Stronger in Europe first, with greek and possibly dutch orders, but also abroad : Saudi Arabia of course, as happened in our reality, but also possibly Australia and, with the lower unit price borne of more important mass production, South Africa (which choose swedish Grippen instead). Brazil might also be interested in the design, both for it's air force and carrier air wing, if the old Foch can launch the plane. Various middle eastern countries like the EAU would also buy it (they are now planning on buying Rafale)
But the main effect would probably be on the JSF F-35 project which would have a smaller export market and less foreign investement, maybe leading to closer US scrutiny and an eventual scraping of the project, especially if Spain, Italy and the UK go for standard aircraft carriers instead of V-STOL plateforms.
This has also an impact on Australia because the Juan Carlos design they bought may well not exist. Thus the australian will probably have to choose between a corean Dodko, a french Mistral or an US Wasp design for it's assault plateform.
Spanish and Italian shipbuilding companies would have slightly less experience with larger ships while british and french one would have a bit more.
European defense integration would be better, with carrier air groups being able to operate indistinctly from any of the 4 to 6 european carrier (1 Spain, 1 Italy, 1 or 2 UK, 1 or 2 France, thanks to the lower building costs) and so many countries using the same planes : maybe some shared training facilities for pilots, both airforce and aeronaval. We already see this with basic flight training of Belgium and France done on a french airbase with planes of both countries used indinstincly for training, here it could be larger.
Dassault plane factory would be a mainly civil company, it's military operations abandonned, or a part of EADS.
The earlier cooperation program may also have revealed design procedures flaws that would thus not happen on the airbus A-380 and other EADS projects, making them appear closer to schedule and planned costs, to the great dismay of Boeing.
Also the program would probably free military money for other projects, especially in the UAV realm.
But the French air force and, particulary it's carrier air groupes, might well be angry at the decision during the late 90's and early 2000 due to the fact there would not be enough Eurofighter to put on the carriers between 1995 and 2003, which probably means that they would not send their carrier group in the indian ocean for the Afghanistan campaign.
The British would probably keep their navalised harrier planes and base them on their new carriers around 2000, thus having more planes availlable for Afghanistan and Irak in 2001 and 2004. The three older Invincible class aircraft carriers would probably be decommissionned earlier and maybe be sold to India or (why not, even if more far fetched ?) Canada.
The spanish Principe de Asturias might also be sold to a second country, maybe Korea or Australia.
Well that could be some of the butterflies coming from a common eurofighter program
