I appreciate that this is not totally applicable if you are strictly a cup and saucer man, but most of the FBO shops in america sell wide-based mugs with narrow openings at the top. These are proof against most in-flight manoeuvres without spilling.
If you aren't passing through the USA in the near future, variations can be bought at a good chandlers, since yachties have a similar difficulty.
I have to say though, that putting milk and sugar into a delicate oriental beverage is a pretty dastardly thing to do under any circumstances.
G