Not exact matches
Bookings made using an upgrade voucher are subject to Avios terms and conditions and are strictly subject to availability which may be very limited or not
available on some
routes at
certain times especially during peak periods.
Off - peak awards are the cheapest, but they are only
available in economy class
on certain routes and during specific time periods.
On certain routes the best fare is only
available if you book through China Southern (as this Google Flights screenshot shows)....
With some, that may include the entire fleet; with others, the frew Wi - Fi is
available only
on certain routes or planes.