There is no such thing as flames that are painted that can't be removed.

The whole scene was funny and who care if the can really be covered or removed. In a comedy things do not need to make sense so just relax and enjoy one of the funnies movies ever made. I feel sorry for people that can't enjoy a picture with out working if every minor detail was right.

PS They were not really speaking Chinese on the plane but who cares, it was funny that is all that matters

The most important thing is sincerity. If you can fake that you've got it made.