I'm am definately not an expert on overflying rights - probably more info on the Flight/Ground Handling Forum. However I know that the former Soviet Union and presumably now Russia charged a significant fee for overflying their territory. It could be that EK are quicker on Thursdays as the pay Russia for overflight rights. If they did not overfly the country the agreement might lapse after a while. There could also be limits in a bilateral agreement.
There was a time with BA / BCal used to fly nonstop twice a week from London - Tokyo & have to stop once a week at Moscow. Flight times between HKG & London used to vary as routings had to vary owing to limited overflying rights. (The block time from HKG - LHR could be as high as 14 hr 40 mins.)
As I say I am not an expert on this, perhaps an expert out there might be able to give a bit more detail.
Last edited by Peter47; 30th March 2012 at 19:16.