Thanks for the helpful information. I'm going to Costa Rica in November for a week, so was hopeful I could take my Mavic Air and not have any problems. I suspected it would be OK, but your post is reassuring. From what I can tell though, it doesn't seem like I have to register if less than 25 kg:
Drones are classified by their weight:
Micro RPAS are those with a weight equal or over 100 grams
Small RPAS with weight equal or over 2 kilograms
Light RPAS those with a weight equal or over 25 kilograms
Big RPAS with a weight of more than 150 kilograms
All drones that weight over 25 kilograms must be registered in the National Registry and have a certificate of aerial navigation provided by the DGAC.
I will check again a few weeks before I go. I'll visit the site you referenced when at home, my wife speaks Spanish, so can help me figure it out.