Costa Rica has two domestic airlines (see schedules and rates NatureAir, SANSA) that operate from two different airports near San José.  The direct flights shown on the route map below last between 15 minutes and an hour, and cost between $40 and $90 each way (plus airport charges, taxes, and fuel surcharge totaling $8-18). 

Both airlines serve essentially the same outlying destinations.  While nearly all flights still begin or end at San José in 2005 NatureAir started adding a few flights from Quepos and Tamarindo directly to other popular destinations and rearranged their schedule to make one stop flights from Arenal more convenient.