Originally Posted by
invisible
Wondering why nobody yet have proposed idea of having speed cut by half if it also means burning half of fuel.
No, we should go up, not down to save fuel, I think.
But as modern airplanes are lighter, how possible is it to allow fly higher (40000-50000ft) which requires larger wing surface but the fewer air resistance and less weather problems (like the QZ8501 and AF447 disasters) can outperform the extra weight.
Don't forget, since the beginning of the jet age over 50 years ago we are not flying a foot higher. The 707 has a ceiling of 43000ft nothing less than the 787. It seems that these values (29000-43000ft) are optimized for jet aircraft of the 1960s and not of the 2010s or 2020s.
But that is an assumption.