Well.....
First of all being an enterprise that will make you money instead of just costing you money you will need a CPL including a local conversion.
The airplane you intend to use should probably be on the host countries registry.
Your Spanish will need to be fluent.
No doubt you will be meddling in somebody else area of operation.
You will no doubt need to bribe.
Private aircraft operations may not be allowed/legal in certain countries.
You may need to file flight plans many hours if not days in advance which makes it wholly impractical for what is basically an "impulse" decision on the side of your prospective customers.
Fuel for piston aircraft may be very hard to find or very expensive.
The expenses of an airplane don't change with geographical location.
So you will end up with prices that the locals are not able to pay so you will be entirely dependent on tourists.
In its entirety its not a good idea....sorry