As the airline industry embarks on efforts to protect the environment, those efforts could end up raising the price of airfare by nearly a quarter.

The airline industry, like many others, is exploring ways to be more environmentally friendly — not exactly an easy task for an industry that flies hunks of metal filled with passengers through the air at high speed. In fact, a fully loaded 737-900 can top 93 tons at takeoff.

Nonetheless, the industry is working on ways to be more climate-friendly. Major options include changing to sustainable aviation fuel, reducing the number of flights, and better organizing routes, according to Forbes.

The changes won’t come without a cost, however, with airline executives already saying that cost will have to be passed to the consumer.

In fact, Forbes reports that Willie Walsh, director general of the International Air Transport Association (IATA) told a Bloomberg conference panel the cost “will have to be borne by consumers, there’s just no way around it.”