While the airline industry and related transportation exchange traded funds have benefited from cheap oil prices, rising energy costs could dampen the rosy outlook.

There are currently no airline-specific ETFs on the market, but investors can still gain exposure to the sub-sector through transportation funds. Fo r instance, airlines makes up 16.5% of the iShares Transportation Average ETF (NYSEArca: IYT) and 25.9% of the SPDR S&P Transportation ETF (NYSEArca: XTN). [Transportation ETFs: Airlines Landing on Higher Profits]

Additionally, the airline sector also accounts for 15.9% of the PowerShares DWA Consumer Cyclicals Momentum Portfolio (NYSEArca: PEZ), which includes six airline companies, with Alaska Air (NYSE: ALK) and American Airlines (NYSE: AAL) among its top ten holdings.

JPMorgan has revised their airline models due to recent traffic and guidance releases, according to a note. The analysts are lowering estimates on a number of airlines due to rising fuel costs.

For instance, JPMorgan expects American Airlines to generate pretax margins of 12% to 14%, from their original 13% to 15% rainge and fuel costs of $1.9 for 2016 resulting in an earnings-per-share of $10.89, down from the original $11.81 estimate. Alaska Air raised its first-quarter fuel assumption to $1.99 from $1.97. The fuel estimates for United Continental Holdings (NYSE: UAL) were raised and revenue per available seat mile was cut due to foreign exchange tailwinds. Additionally, the analysts diminished estimates for Southwest Airline (NYSE: LUV) due to the revised fiscal year fuel guidance.

However, Delta Air Lines (NYSE: DAL) fuel estimates were lowered to $2.35 from $2.4, raising the company’s earnings per share outlook.

Looking at the related ETF holdings, IYT includes 4.6% ALK, 4.5% UAL, 3.1% LUV and 3.1% DAL. XTN follows a slightly more equal-weight methodology, allocating 2.8% ALK, 2.5% AAL, 2.4% UAL, 2.5% LUV and 2.2% DAL. PEZ tracks 3.8% ALK, 3.8% AAL and 2.8% LUV, 2.6% DAL.