With the covid pandemic, companies have now a much more flexible cancelling policy, allowing passengers to cancel a flight and giving them an e-credit to be used with them. I am concerned though that this would restrict a lot my flight options if I were to use that e-credit later on.
How flexible are these e-credit in general? That is, can you buy a flight from company B on company A's website? My first impression seems that it is not possible: having credit with Delta, I seem unable to buy an Air-France ticket, although Air France is their partner, and they even operate some flights together.
Now I also know that sometimes you might be able to buy tickets from a company that are not advertised on their website, but that show up on some aggregator website. I did this once for a complex multi-city ticket involving three distinct companies, though I bought it from the company offering the first flight.
To summarize, how much will I be bound to using credit within the same company? Is the trick (calling the company to ask for an unadvertised ticket) likely to work, or is the answer just it depends/no guarantee?