Year end is traditionally the time for predictions. IATA has just released its Airlines Financial Monitor for November-December 2017 which contains a few that warrant further thoughts.
According to IATA, "Industry-wide passenger yields are currently broadly unchanged from where they were a year ago. Against a backdrop of robust global economic growth, and rising input costs, we forecast yields to rise modestly in 2018."
Yield is the average fare paid per mile per passenger. It's calculated by dividing passenger revenue by passenger traffic which is measured by RPKs (revenue passenger kilometres).
Now airlines' costs are pretty much fixed per aircraft per route so their commercial aim is understandably to raise yield.
Higher fares is one obvious way and with the oil price up after a three-year slump, using the "it's not my fault" explanation is a convenient cover for raising fares. However, markets are competitive and you can't raise fares and also maintain your market share if others flying the same route don't do so as well.
However it's a time of airline consolidation which in itself reduces competition. It can also combine services to cut capacity. Capacity may be cut too by swapping aircraft or reducing services so upward pressure can be caused by reasons other than higher input costs.
But for businesses the biggest explanation of rising passenger revenues is not a spike in fares but an increase in travel generally and in premium classes specifically.
Our chart this week comes from IATA's report which shows what is happening to the growth of premium traffic and fares.
And this is probably where the price of oil is having the greatest effect. If the price of oil drops, business travel, especially to energy-dependent markets such as the Gulf, falls. The price of oil goes up when demand starts to rise in relation to supply and that usually means an upturn in market indicators. Organisations will travel to grow their markets and their businesses.
And, as IATA's chart shows, premium travel has revived in Asia.
It also, more surprisingly perhaps, shows that premium traffic within Europe, thought to be moribund, is growing strongly. Any growth would admittedly look strong as usage had slumped so much in recent years due to the post-2008 feeling that flying premium was a cost companies didn't need to incur when their execs were on flights of only an hour or two's duration.
The reasons could have as much to do with lessening service and included amenities and more restrictive terms and conditions in economy class as they do with a wholehearted return to business travel.
But there is no doubt that the demand for front of cabin flights for intra-European trips is increasing.
There is more than one way in which that modestly higher yield, which IATA predicts, might come to pass.