s'alright, welcome to AirlineMogul.
AirlineMogul restricts route origins to focus cities [no point to point flights] at the moment, and this is unlikely to change in the presently forseeable future. At the onset you pick a city for your first base to be at, this is where all your routes can originate from or fly to [depending on which leg it's on]. A plane can connect through cities ONLY SO LONG AS one of the cities in the pair is a focus city. [so. for example: you can fly FC1->Airport A with one plane, and if you have a second focus city you can create with that same plane a route from FC2->Airport A, as the two routes connect through Airport A and each route has at least one focus city.]
A player by themself is allowed only 6 focus cities on their home continent/region [so, for example, if you started in our North America (US/Can), you can only create focus cities in North America]. A player needs 4 gates at a target airport on their home continent to create a focus city, and a focus city costs 50x[airport's monthly rate] to create.
A player can also, however, join an alliance. Some alliances allow shared use of their members focus cities. Please note these numbers are shared alliance wide [so 20 routes means 20 routes for the whole alliance who isn't based at that airport themselves]. The catch is you [by joining] automatically share your focus cities for whatever number the alliance defined level is, which can be [as some players may tell you from personal experience] quite detrimental or can be [as others can tell you] quite useful. To use an alliance members focus city you need free cap room in the route cap and a gate at the airport.
Feel free to pepper me with further questions if you like. I hope my answer helped.
