as the guy behind the actual route script... here's how i see it (and yes, it largely matches LOT 737's drawing).
You're allowed to arrive and depart from any airport SO LONG AS one of those airports is a focus city of yours, or an alliance focus city you have access to. (otherwise, round trips wouldn't make sense). So. if you're flying AP1 - AP2 at 1.0 frequency, you're selling tickets in both directions.
This means, that the drawing holds up, because it essentially goes AP1-AP2-AP3 day 1, then AP3-AP2-AP1 day 2. provided either AP2 is an available focus city, or both AP1 and AP3 are available focus cities. (it doesn't matter which.)
the scenario that is allowed at present in game that's terribly illogical and defies the laws of physics (yet is at present perfectly legal) is the following.
assume AP1 is a focus city and all following are one-way flights.
AP1-AP2;
AP1-AP3;
AP1-AP4...AP1-APx.
at no point in the 24 hours does the plane make the hop from the appropriate number of one-way flights back to the originating city. I can write in something to automatically put in a ghost return flight, but this doesn't always work as i've presently got no way in the backend to catch which route has the ghost return flight; or worse yet, no way to optimize which has the ghost return flight as the third one-way is created. logically any airline would want a ghost return flight on a 25nm route as opposed to on a 1000nm route.
Now. i know how to easily generate the code so that only planes flying less then 2 one-way flights have available to them one way options. that's easy. BUT it's incredibly... incredibly shortsighted. and that part bothers me. See the following.
assume the following: AP1 is a focus city; AP3 is a focus city; all flights are one-way flights.
AP1-AP0;
AP1-AP2;
AP2-AP3;
AP3-AP4
The above is completely valid, and it is comprised of FOUR one way flights. shock. awe. STILL i can't just say 2xfocus cities it passes through. as what if it did this instead?
AP1, AP3 are focus cities, all flights one-way flights.
AP1-AP0;
AP1-AP2;
AP1-AP3;
AP1-AP4
That's 4 one-way flights, and it passes through 2 focus cities, but two of them are officially illogical routes.
I'm hung up on, and have been for a little while, sorting out how to detect this scenario and enact the proper rules. and not only that, how to do so efficiently. (i assume nobody will play if it takes more then 25 seconds for the create route page to load each time. in fact, i get annoyed if it takes over 5 seconds.).
oh-ho-ho. it gets even more fun still.
What if.
AP1 is the only focus city an airline has but it does this: (all one-way flights).
AP1-AP2;
AP1-AP2;
AP1-AP3;
AP1-AP3;
AP1-AP4
that's five one-way flights. and it's perfectly logical by the laws of physics (as it winds up being AP1-AP2-AP1-AP3-AP1-AP4, reverse the next day). it also abides by the reigning rules of the game of the 2x.5 rule.
-_-. anyone got ideas to help me make a robust, yet logical and reasonable check for any loops in routes, and the ability to pass through multiple focus cities within the present, non-timetabled format?