I would like to know if this API also allows for calculating flight routes. For example, if I request a route between Frankfurt and Singapore, will it provide me with the route by road or by air? I noticed that transportation modes such as train, tram, and subway are available, but not air travel, which is why I am asking. Thank you in advance for your response.
I have thousands of departure and arrival cities traveled by travelers, and I would like to find out how many kilometers they have covered. I am not familiar with coding, but I understand that this API can help me do that. I want to make sure that air travel routes are accurately taken into account, as they represent the majority of the trips.
You already answered your own question. No, it is not. Air Travel is not a supported mode.
You can check out their supported modes in their documentation and as of today they are all earth bound, no planes.