I did the journey from Fortaleza to Jeri a couple of days ago. There are various ways of doing it (hire a car, private 4x4/minibus, helicopter etc) but the cheapest is the public bus.
It is operated by Rendencao (www.rendencaoonline.com
) and tickets can be bought in Fortaleza airport at the booth to the right of the Ceara Tourism Information booth (a few to the left of Avis). There are two buses a day (maybe a third in high season) at around 10:00 and 18:00. My bus turned up at 18:45 and I don't think this is unusual - expect it to be late.
It pulls in outside the door near the ticket booth at the very end of the terminal, near the taxi rank. It stops at a few places on the way, picking up more people, then dumps you in Jijoca. After a long wait an open sided bus arrives and the same ticket gets you on that, to Jeri. Its a bumpy ride of about an hour, the last 30 mins of which is along the beach.
The whole journey is 6-8 hours and costs R$38. The coach to Jijoca is really comfortable but the bus after that is pretty painful. It's a relatively straightforward journey though.
Hope this helps.