Aeroclub... Yes but for mebers only. You need to convince one of the members to take the ralley out for the tour. Ultralights are privately owned, I tried to get e a ride but my inability to communicate in French seemed to hinder my attempts.
There is a company in PNR called Aeroservice. They have anything from a BN2 Islander to AN24 available for charter.
Sorry no contact numbers.
They do operate out of Brazza too. Prices? Supply and demand.
Personally I would stay out of the river region, especially the upriver. Quite wild up there. If you insist going for a fishing trip try looking up info on the South African fishing magazines and websites.
There are some barges that go upriver for days with all sort of supplies and come back with stuff out of the jungle. You might think about hitching a ride with one of these, get your own cabin (if available) to sleep in and fish during the day when they stop in many of the little villages. Your catch could even include the Hanta or Ebola
