The flight planning aspect can be done. In ways it has been done by gliders. The real difficulty is convincing a very conservative industry to change.
The mechanical/aerodynamic aspect is much more difficult, but some people are making real progress here (see the synergy homebuilt). Still, we don't have a cost effective way to change the shape of a wing like a bird does. So we're stuck making some (though not as much as is currently standard) tradeoffs. As mentioned int he article, the albatross has a L/D of 20, which is certainly achievable with current technology
Again, the big trouble is convincing a conservative industry to change. They're still not catching up with canard wing designs from the 1970's.
EDIT: As marvin points out gliders use different techniques. As you might expect you'll get the best results using an ensemble technique - take advantage of thermals when possible, use wind where possible, plan for most fuel efficient altitude/temperatures, etc.
You're certainly correct. I was getting L/D and glide ratio mixed up. Further I was thinking about the state of the art in small aircraft - the Cessna 172 or Cirrus SR22. Neither particularly good in this respect.
L/D and glide ratio are equal numbers. It's a matter of basic geometry. While different concepts, they'll always be the same value for a given aircraft.
The mechanical/aerodynamic aspect is much more difficult, but some people are making real progress here (see the synergy homebuilt). Still, we don't have a cost effective way to change the shape of a wing like a bird does. So we're stuck making some (though not as much as is currently standard) tradeoffs. As mentioned int he article, the albatross has a L/D of 20, which is certainly achievable with current technology
Again, the big trouble is convincing a conservative industry to change. They're still not catching up with canard wing designs from the 1970's.
EDIT: As marvin points out gliders use different techniques. As you might expect you'll get the best results using an ensemble technique - take advantage of thermals when possible, use wind where possible, plan for most fuel efficient altitude/temperatures, etc.