Like bacon and peanut brittle, or Bing Crosby and David Bowie, air travel and Earth Day make unlikely bedfellows. After all, one cross-country, round-trip air ticket can create a warming effect of two to three tons of carbon dioxide per passenger. And the inconvenient truths about carbon-offset purchasing plans include high prices and mixed reviews.

Fortunately, some global airlines are stepping up to the sustainable plate, in an attempt to raise culinary consciousness in the not-always-eco-friendly skies. So put down your tray tables, and get ready to go green.

KLM: The national carrier of the Netherlands knows about sustainable seafood. It uses World Wildlife Fund guidelines to analyze the origin of all fish served on board, shying away from overfished crowd-pleasers like tropical shrimp in lieu of savory smoked salmon that has been certified by the Marine Stewardship Council. The drinks cart does its part as well, pouring single-origin and sustainably farmed teas and coffees.

Etihad: In 2012, Etihad purchased three beehives and 200 free-range hens to raise at Abu Dhabi's first organic farm. Now, its eggs and honey are used in Diamond First Class meals. The airline's first all-organic dish, a locally grown caprese salad, was also introduced in 2012.

Virgin America: In addition to its LEED-certified headquarters and fuel-efficient fleet, Virgin America serves only fair trade coffee, plus snacks that make an eco-effort. Organic 479° popcorn, Krave's hormone- and nitrate-free turkey jerky, and sustainably sourced Hail Merry gourmet nuts are all available on Virgin flights.

Hawaiian Airlines: To cut cabin waste, all meals on Hawaiian are served with biodegradable cutlery, in packaging made of recyclable materials. The airline also supports local, small-batch producers, serving snacks like the Big Island's beloved Punalu'u Bake Shop's macadamia nut shortbread cookies on board.

Cathay Pacific: In 2012, the world's largest air cargo carrier made, um, waves when it announced it would no longer carry unsustainably sourced shark's fin, a controversial culinary item on par with foie gras. The impact of Cathay's decision extended beyond the tarmac, too. That same summer, the Chinese government decided to stop serving shark's fin at all official receptions. Score one for the sea.