Yes, there are designs using forward canards, for example the Rutan VariEze, Long-EZ and Beechcraft Starship are excellent examples. There is also the Eurofighter Typhoon.
But perhaps the best example is the first powered airplane, the Wright Flyer, which used a forward canard.
Are there any designs where all horizontal surfaces support the craft
in the air?
Canards, as per the designs of Burt Rutan, for one. Not to mention the Wright brothers!
Also, many "free-flight" model airplanes (which operate with no pilot guidance of any kind) have been designed with lifting tails (horizontal stabilizers), with tail ...
The lift equation:
Lift = wing area x Coefficient of Lift x air density x V$^2$
provides three variables to lift a given amount of weight: Angle of Attack, air density, and velocity.
Aircraft have the least amount of drag per unit lift at a specific AoA, so best to keep it there. Speeding up a little is a very good idea but there are 2 factors with the ...
Because the density of the air decreases with increasing altitude. Thus to achieve the same net lift, to reach equilibrium with a given weight, the wing must have a higher angle of attack.
The higher angle of attack also increases drag which requires additional thrust to overcome.
Thrust available also decreases with increasing altitude due to decreasing air ...