The phrase "jumbo jet" refers to a type of very large airplane, specifically the Boeing 747, which can carry a lot of passengers or cargo over long distances. Full definition
But ethanol will not work for the larger jumbo jets in commercial aviation because it does not pack enough power per gallon. (scientificamerican.com)
In fact, as this great video shows at the end, flying is cheaper than ever, half of what it cost thirty years ago, when they were already flying jumbo jets. (treehugger.com)
Around that time, he had already noted rough estimates of how many jumbo jets full of sulfur compounds would be required each year to counteract global warming. (dotearth.blogs.nytimes.com)