In terms of TACA and Copa...
Taca is Based in El Salvador and Copa in Panama.
Both fly flights in an out of every Central American Country (except Belize)
I know there is an openskies between all of the central american countries and the usa... but Idk if they are between each other. Which frustrates and confuses me as to why TACA has hubs in SJO,MGA,GUA,SAL,PTY,TGU,etc...
If i remember correctly, TACA has US registrations on their planes. Copa does not , but Continental (Now United) has a stake in the carrier.
Idk if the USA connections (corporate or political, who knows) allow the carriers to operate regionally or if it is a little known document or something. Bugs me so much.
A side note- Taca is basically the national airlines for each central america country (except Belize again) merged together under one name. Only one national carrier still has a a "name". That is Lasca, the former Costa Rican National carrier.
From Wikipedia, the five airlines : Mainline/International
TACA International (TA) (El Salvador)
Lacsa (LR) (Costa Rica) Lacsa is the only airline of the group that still operates international flights with its own flight numbers. Its hub is at Juan Santamaría International Airport in San José, Costa Rica.
Nicaragüense de Aviación (6Y) (Nicaragua)
Aviateca (GU) (Guatemala)Regional
Regional (GU) - Formerly Inter, it operates under Aviateca's code.
SANSA (Costa Rica) (RZ)
Isleña Airlines (WC) (Honduras)
La Costeña (Nicaragua)
And of course, they are merged with Avianca too. The branding is different but the FF programs and booking are tided together (Trust me IK i have a FF card with them
TACA is sucha complicated airline its not even funny
Copa is totally different. They are one company, with the exception of CopaAirlines Colombia, which is a totally separate carrier but it is under the same holdings company as Copa.