timber line, timberline, tree line - line marking the upper limit of tree growth in mountains or northern latitudes snow line - the line on a mountain above which there is perpetual snow and ice fault line - (geology) line determined by the intersection of a geological fault and the earth...
“…at some point the fuel economy of the aircraft is going to make a difference to the cost base of the operation.” But for Japan domestic ops, they rarely reach anywhere near that “point” because 99% of all frequencies are well within 3hrs sector duration. Even the longest sector ...