just a guess = human powered aircraft like the gossamer condor or the one that flew around the world nonstop cant remember the name
The worlds stealthiest airplane would probably be the size of your moms pubes
It is the An-225 with a 1.3 million pound takeoff weight it makes the worlds heaviest airplane.
the life of the teenager
Antonov made the worlds largest plane called The An-225 Mriya.
JUmbo 257 100 km per hour
The superlative of efficient is "most efficient."
Depends on your definition and what kind of airplane. Large commercial airplanes are the most efficient way to move people. Small airplanes are horrible wastefull things.
The worlds lightest airplane is I believe the ultralight. Now ultralight aircrafts come in many different shapes and sizes but they are the "Family" of the lightest planes. To see what they look like, go to google.com and type in pictures of ultralight planes.
Spur Gear is the most efficient
More efficient and most efficient are the comparative and superlative forms of "efficient".
The most common type on airplane flown is the 747.
the airplane with the most fuel