I believe the web site (in Spanish only) for Atlantic Air is http://www.atlanticairlinesint.com
The following page has flights and fares from Belize City to Roatan, La Ceiba and San Pedro Sula: http://www.atlanticairlinesint.com/html/itinerario_y_tarifas.php
The flight from BZE to Roatan is supposed to depart Mon-Wed-Fri at 4 pm and is supposed to arrive Roatan at 5:45 -- but Atlantic flights are not always on time! -- and cost US$162 one-way or US$291 round-trip.
I saw a trip report, not sure where, just the other day from someone who had recently flown Atlantic from San Pedro Sula to Belize City. Said it was okay, except that it was delayed by several hours.
I guess Maya Island Air's flights between Savannah and San Pedro Sula, which only started a few months ago, have already been discontinued.