In the third quarter, the average fare for a business trip in Philadelphia fell 40 percent.

But the average domestic fare fell 1 percent, to 13 cents a mile.

It cut ticket prices to encourage customers at a time when many felt doubts about flying; its average fare fell 8 percent over the year.

After the change, the fare dropped to $460 and then fell again a few weeks later to $380.

Between 1984 and 1988, fares fell 15 percent on average, that study found.

Indeed, when fares have fallen, ridership has invariably picked up.

And international fares sometimes fall below the levels set by the transport association.

The reduced seat weight would mean more could be crammed in and fares would fall.

If you want to go in summer, do so towards the end of August, when fares fall.

But fares have fallen to slightly less than the national average, as measured in dollars per mile, he said.