Anyone interested in knowing about the health of the world's economies could do worse than look at how full aircraft are at the front compared to the back. IATA monitors the utilisation of premium classes carefully, through its monthly Airlines Financial Monitor.
Our chart this week comes from the most recent edition of the monitor.

The chart needs a little explanation. The vertical axis shows the difference between premium and economy fare increases for the year so far. This means that routes whose circles are above the line have seen a larger increase in premium fares than economy fares on the same route in percentage terms. The size of the circles indicates the relative sizes of the premium markets — the North Atlantic routes are still the biggest market for premium travel.
The horizontal axis, meanwhile, shows how premium passenger traffic has grown compared with economy over the same period. Circles to the right of the line indicate that premium cabins are getting fuller faster than economy cabins.
Premium demand is closely correlated to confidence and good economic news — better trade global trade is contributing to the growth in Asia and across the Pacific.
The rise in demand for premium travel within Europe could finally indicate a backlash over the slashing of frills, driven by the rampant low-cost carriers. Relatively lower premium fares will also have helped.
Premium travel between Europe and the Middle East is proving less popular.