re: "oneworld" award (140K/280K/420K) Planning - The Definitive Thread
Apologies for getting MXP-JFK wrong. I had no idea AA serviced that route.
I don't know why the Oneworld planner is in kms but the limit is 35,000 miles or 56,315 kms and surface segments are allowed but count towards the total mileage.
I think that is misleading error message trying to tell you that you are trying to enter/exit your country of origin more than once. I don't know where it is written in the terms and conditions but I do not believe you can leave your country of origin once you have returned and have never been successful. Try out some different combinations.
Not sure what is wrong with LHR-GLA. Should be OK but again that is only a short flight and perhaps can be booked separately.
Here are the main terms and conditions for Oneworld award bookings and just scroll down to 14.5.
