Southwest (LUV), for one, noted on its earnings call that, given expected market prices for aviation fuel and already in-place derivative contracts, it would save around $500 million year-over-year in the first quarter alone. Rival United (UAL) reported that it saw the price of fuel drop nearly 15% in the fourth quarter of 2014, and more than 5% for 2014 as a whole, representing $670 million in savings for the airline compared with 2013. Alaska Airlines (ALK), a smaller carrier based near Seattle, said it spent 13% less on fuel in the quarter and 3% less for the full year.

Earlier this week, Delta (DAL) announced it was expecting fuel savings of $2 billion in 2015 due to dropping oil prices. The price of a barrel of oil has fallen by about 60% to below $50 since last June.

With all that extra money in their coffers, airlines appear focused on rewarding shareholders, but not customers.

Southwest has long focused on sending excess profits back to shareholders, and CEO Gary Kelly said on CNBC Thursday that he thinks other airlines have copied that strategy.

“I think shareholders are more active and have demanded that,” he said.

In a conference call after the airline’s earnings were announced, United CEO Jeff Smisek said the carrier would use fuel savings to speed up the company’s long-term goals, including share buybacks.

Paying down debt is also a popular use of the savings. Carriers are currently carrying $70 billion in debt, according to Jean Medina, a spokeswoman for industry trade group Airlines for America.

Although fuel costs are declining, ticket prices are not seeing the same big drop.

In the Consumer Price Index report issued last week, the airline fares index fell just 4.7% year-over-year in December. The daily price of a gallon jet fuel, meanwhile, went from $2.96 to $1.80, a drop of nearly 40%.

There have been a few isolated attempts to give customers a break. Earlier this month, Alaska offered a 20% savings for customers who put in the promo code “FUELSAVINGS” when purchasing a ticket.

Customers who own airline stocks could see some benefit, however. Airline stocks should start to gain altitude as a result of the airlines’ fuel savings, said JPMorgan analyst Jamie Baker.

“The market is only putting a fraction of value on these fuel savings,” he told CNBC Thursday, adding that, despite a healthy 2014, the biggest U.S. carriers could still see “market trouncing returns.”