The secret to snagging a cheaper flight this fall

Airfares this fall expected to drop 8%

For all the complaints many people have about taking a flight these days, here's a bit of good news even the most jaded traveler will enjoy.

Airfares are dropping and this fall could be a great time to save money on a flight.

"We think airfares will drop, on average, more than 8 percent through October," said Patrick Surry, chief data scientist at Hopper, a research firm that tracks more than 3 billion price data points related to airfares.

Surry expects the average domestic airfare to fall as low as $213 round trip this October. The average domestic ticket sold for $232 in July, the most recent month of price data finalized by Hopper.

What's driving down prices?

The combination of lower jet fuel prices and excess capacity is forcing airlines to lower prices in order to sell seats.

"Certainly, there's a big seasonal effect driving down fares," said Surry. "Airfares almost always come down in the fall because there are fewer people flying."

While the drop in airfares is great news for those looking to book trips, the decline will reinforce a growing concern among investors about airlines struggling to grow passenger revenue.

Most airlines have forecast a third-quarter decline of 3 to 6 percent in passenger revenue per available seat mile, or PRASM, the metric used to measure airline revenue.

That drop is the main reason airline stocks have struggled over the past year. Many carriers have told Wall Street they expect the fall in PRASM to bottom out in the third and fourth quarter before slowly rising next year.

In the meantime, travelers who have yet to book a trip this fall are finding this to be an unusually profitable time to line up a trip. Even international airfares are down, depending on the region.

"We're seeing more flash fare sales where carriers offer tickets for half price for a limited period of time," said Surry. "They need to fill these planes even if it means selling seats at lower prices."