Ilha Grande has no airport. You arrive in Rio de Janeiro — Galeão (GIG) for international, Santos Dumont (SDU) for domestic — then reach one of the four landing stages by road, 2 to 3 hours away. The crossings are detailed on the Getting around.
The simplest connection from Portugal and much of Europe, with a non-stop flight to Galeão. Handy for picking up the coast road the next morning.
Official siteflytap.com→A direct link from Paris-Charles-de-Gaulle to Galeão. Allow a night in Rio before setting off by road: the transfers to the landing stages leave early.
Official siteairfrance.fr→The long-haul airport. This is where flights from Europe land, and the starting point for road transfers to Conceição de Jacareí and Angra dos Reis.
Right in the centre of Rio, handy for Brazilian domestic flights — useful if you are continuing to São Paulo or the Nordeste.