In Rio city, the kite spot is in Barra da Tijuca beach, open ocean and the wind is not always there, its great for the people who live in that city and specially around that spot, because if its windy they bring their kites, if its not windy, they just hang out at the beach which is full of pretty ladies. But the problem is that this beach is a little far away from the classic places tourists usually go or stay, like Ipanema, Leblon and Copacabana beaches or Santa Theresa hills neighbourhood. Barra da Tijuca has no tourist attractions near by and you could only convince your friends to go there if they really just want to stay at a beach the whole day. The beach there is nice and not as crowded as the famous ones I mentioned. You would have to reserve an entire day to kitesurf there, so check the forecast before you go. Other famous spot in the State of Rio is Lagoa Araruama área(lagoons), far from the city and you would have to sleep there.
But even if you don't kite, the city will be really crowded of people from all over the world, it should be fun.
Azul airline will probably be the cheapest one, there was just a press release where they say they will increase their number of flights 30% and the maximum fare between cities having games will be 999 reais(or something closer to 450 USD) during the world cup. But check
www.voegol.com.br and
www.tam.com.br as well, sometimes they have" last minute deals".Flight to Fortaleza might be this price, but pousadas(hotel or Bed&Breakfast) will be still cheap, I really doubt the kitesurfing spots will be "contaminated" by the world cup prices "dementia". Wind and weather will be perfect basically everywhere in Fortaleza área(thousands of kilometers around).