Those little planes made from foam with a 2100mah battery pack will give you 12 min of airtime.
You can extend it by using the lithium 123a batteries for the sure fire flashlights. Obviously If it is a one time use plane you should use the throw always.
Construction of these is very simple. You need to get some blue or pink styrofoam for the materials.
Cheapest but ugliest way is to print a pattern on paper, stick it to the foam with some glue stick, and cut it out with a jigsaw. You will need a lot of post finishing work.
Best way it to get it lasered at a sign shop.
Now here is the interesting thing. You do not need to shape the airfoil with this method. However your performance will not be as good as shaped wings.
These planes only have 2 controls. They use a servo that when it turns one way, one goes down and the other goes up on the wings. The tail handles angle so to turn it you bank to the side and use the elevator.
If you want to go bigger, bigger range, bigger payload, you will need bigger wings, which of course means you need reinforcement.
You can embed carbon fiber tubing into the wing and you are ready to go.
Here is a alternate method.
You get the airfoil section and draw it in CAD. You only need a 2D representation.
Then you get some thick foam insulation, 1-2 inches thick.
You laser out the shape of the airfoil and you include holes to use either very thin aluminum tubing or carbon fiber tubing to fit in the holes. This is your cross support.
You then laminate the pieces together to form a very strong wing yet light weight. Gorilla glue is very good for this.
For the flaps you can use strapping tape or hinges. The tape method gives you plenty of surface area coverage. You can glue the tape on to make sure it does not come off.
Then the servos attach to the center with some stainless TIG weld rod for the levers.
You use the arduino pilot board, motors, motor controller and batteries to assemble the plane.
DiY Drones has the specific info to set it up.
Now it is possible to make a manned plane using this method in the form of a hang glider type plane, although this is beyond the scope of this article.
So here is the scenario. You are in your forward position. You do not have the manpower to send out patrols all the time. Or you are sitting outside somewhere and need to do a sneak and peek.
This is the tool to use. The US military uses the Raven which is a extremely over priced model airplane. You got the same tool for a couple days wages.
If you 3d print the motor mounts, camera mounts servo mounts, and landing gear you just saved from having to buy those parts too.