'The congestion, which looks likely to be curbing growth, is the price the industry has to pay for the lack of investment in, and appreciation of, cargo handling,' said Clive managing director Niall van de Wouw.
Week-on-week global load factors fell 1.5 per cent, in the week to November 10, said Clive. The same week saw a 5.5 per cent fall in global capacity, which should indicate higher load factors - but it seems demand fell.
While forwarders are reporting strong demand for air freight as the peak season takes off, the data suggests congestion on the ground is curbing volumes.
'There is a lot of congestion - in Melbourne, Baku and Chennai, as well as Europe and the US,' said one forwarder. 'In fact, it seems to be any city with a large piece of tarmac that a plane lands on.
'And charters are currently being refused as congestion is not allowing them to be discharged.
'But there is definitely higher demand. That is happening. Sea freight disruption and schedule failure are creating distressed ocean freight, and conversion to air freight - whether to get consumer products into stores for Christmas or components for manufacturing - has accelerated,' he said.
Clive data shows volumes out of Shanghai - which has been restricted during China's International Import Expo, with permission for charters denied - fell 16 per cent, while southern China volumes fell 12 per cent. Hong Kong appeared to take up some of the slack, with volumes up 16 per cent.
Airports across the US and Europe, notably JFK in New York, Heathrow and Frankfurt, are facing severe delays as handlers battle a shortage of labour. But according to Fraport, the operator of Frankfurt Airport, there are other issues preventing the fast processing of shipments.