With guidelines for aviation emissions glaringly absent from the Kyoto Protocol, airlines, airports and aircraft companies pledged to remedy the omission with a plan to cut airline emissions by half by the year 2050. The BBC reported that British Airways CEO Willie Walsh said the proposals, "represent the most environmentally effective and practical means of reducing aviation's carbon impact."

Environmental groups seem skeptical and are weighing in on the proposal. If you'd like to weigh in, check out the following articles: BBC's Airlines Plan to Cut Emissions and AFP's Airlines vow to cut carbon output by 2050: report .