WASHINGTON — Fifteen airlines and air cargo carriers, including Hawaiian Airlines, said Tuesday they’ve signed memorandums of understandings that could lead to the purchase of hundreds of millions of gallons of fuel made from either coal or camelina, a weed that’s a cousin to canola.

The Air Transport Association said airlines from the United States, Canada, Germany and Mexico have signed memorandums with AltAir Fuels LLC of Seattle, which contemplates producing about 75 million gallons of fuel a year from camelina or similar feedstocks, and Rentech Inc. of Los Angeles, which contemplates producing about 250 million gallons a year of fuel derived principally from coal or petroleum coke.
United Airlines Chairman Glen Tilton — who is also chairman of the airline association — said the memorandums show airlines are actively working to stimulate competition to jet fuel made from petroleum.
Tilton said in a statement that discussions are also under way between airlines and other fuel producers and the U.S. military about additional alternative fuel projects.
Twelve airlines — Air Canada, American Airlines, Atlas Air, Delta Air Lines, FedEx Express, JetBlue Airways, Lufthansa German Airlines, Mexicana Airlines, Polar Air Cargo, United Airlines, UPS Airlines and US Airways — have signed memorandums with both producers, the airline association said. Also, Alaska Airlines and Hawaiian Airlines signed the memorandums with AltAir, while AirTran Airways signed a memorandum with Rentech.