Any suggestions for airfare/airline from Cancun down to Caye Caulker?
How much?
thanks

Sorry but travel between Caye Caulker and Cancun by air is not realistic.

There is a way, go via Belize International to Tikal (Flores, Guatemala) and then to Cancun.

Another way is to go from Caye Caulker to San Pedro, Ambergris Caye then to Corozal by Tropic or Maya Island Air. Cross the border using taxi or public transportation into Chetumal, Mexico. Then take a flight from Chetumal to Cancun using AeroCaribe.

None of these methods are cheap.

The bus between Cancun and Chetumal takes about 6 hours using Primera Clase (First Class) buses. This is the most inexpensive route and very well traveled. Lots of buses each day.

When you are traveling from country to country, one must fly into an airport that has a customs and immingration unit, only the International airport, Philp Goldson has this.
When did aerocaribe start flying between Chetumal and Cancun again? Last I was aware there were no flights on this route.

Cancun-Chetumal service is on again off again according to the whims of the decision makers at AeroCaribe/Mexicana. They also used to have flights Cancun-Belize International but they have been discontinued for over a year. The prices were high and most likely due to that the route wasn't profitable as many opted for bus service instead. I used them because it was fast and I wish they would bring the flights back.