The iShares Transportation Average ETF (NYSEArca: IYT), the tracking exchange traded fund for the Dow Jones Transportation Average, fell nearly 2% last Friday, extending its one-year slump to nearly 15%. A technical look at IYT and the Dow Jones Transportation Average does not provide much in the way of encouragement.

So far this year, the railway industry has been weakening on lower rail traffic after the drop in energy prices, notably from oil and coal companies. Over the first 35 weeks of the year, U.S. railroads experienced cumulative volume that was down more than 4% year-over-year. However, the pressures may have already been priced in, and the industry has a number of factors that will help support further growth.

Even strength from airline stocks, which have been bolstered by an ongoing downward spiral in oil prices, has not been able to prop up IYT as railroad operators and trucking firms struggle. Airlines are perhaps the brightest spot within the transportation industry at the moment. Falling crude oil prices have supported airline stocks and the U.S. Global Jets ETF (NYSEArca: JETS), the only dedicated airline industry-related ETF on the market. [Oil ETFs Plunge to All-Time Lows]

“Transports peaked over a year ago and have declined nearly 17%, since November of 2014. The decline now has Transports testing rising channel support and another key support line that dates all the way back to 1999. At the same time, Transports are testing a Fibonacci 161% extension level, at the same time,” said Chris Kimble of Kimble Charting Solutions.

Airlines are also paying down debt while free cash flow is rising. Debt as a percentage of operating revenues has declined to 41.4% in 2014 from over 65% in 2010. Free cash flow is expected to rise over $15 billion this year from close to zero over the past couple of years, as ETF Trends reported last week. [Trouble for Transportation ETFs]