Although I haven't bothered to check, EK may not currently have any aircraft with a negative performance degradation. Despite other comments here that wasn't always the case, especially on the GE powered 777's.
Most of the early 300-ER's were running degradations in the range of over -3.0% and still burning substantially (tons not hundreds) of kilos less fuel than the -3% flight planned. Let's face it, TC ordered the aircraft on the back of published performance specs so it's little wonder that he went on to order 170+.
They seem to have sorted out the true performance figures and Boeing are delivering aircraft with 0 which just means they have the data to sharpen the pencil to an accurate number.
Can't speak for the bus, but the 380 economics obviously work as well otherwise they wouldn't be clogging up the pavement.