Just as some airlines are eliminating onboard food including those half-ounce bags of salty snacks, Denver based Frontier Airlines is now selling sandwiches, salads and fresh fruit cups on select flights. The items come from Udi’s Handcrafted Foods in Denver, which also supplies the airline with Udi’s Granola. The carrier also sells Rockstar energy drinks on all flights ($3), but you’ll have to fly more than 540 miles from Denver before they’ll sell you Dansai bottled water for $2.