Not too sure what you mean by modifications, but I'll have a go.

A basic one is those little flaps on the side of the wings; always a good one to keep it stable. I'm not sure what the different between flaps that go up or down.

Another is the stabilizer, by a simple vertical cut in the body of the airplane (The strip you hold), then folding the other way so it makes a triangle which stabilizes the airplane.

Then there is my personal favorite: ailerons. If you don't know what they are, I advise you to look them up, they are very interesting.

You can make them by cutting two slots out of the back of both wings. Make two cuts on a wing and you should get a small rectangle that can be folded up or down. Do this to both, and by changing their position before flight, they can make the plane do many things, it's cool to experiment.

Hope these help!

Generally, the best way to construct paper airplanes in an assembly line fashion, is to complete each assembly step for the entire production batch, before proceeding to the next step in the assembly process.

The primary reason why the aeroplane was invented is that man had seen the birds fly and he wondered if he could build a machine that might take him up into the air.

A paper airplane can be rolled using the surfaces used on real aircraft. Ailerons, elevons, spoilerons or differential deflection of horizontal stabilizers (which, in most semi-tailless paper airplanes is essentially the same as elevons).

it does effect the plane because the wider the wings are the easier it will be to gain lift and the more narrower the wings are the harder it will be to stay in the air longer.

Paper airplane's velocity can be measured as any other object can be determined by measuring its displacement over time. In other words, time the glide and measure the distance. Then divide the distance by the elapsed time to get the average velocity of the flight.

I am doing a science project in school. Subject: How does temperature affect the way a paper airplane flies?

Take a piece of computer paper, and fold it hot dog style. Unfold and fold the top corners to the crease you just made. No fold the new top corners in. I should look like two stretched out triangles. Fold it in half so the triangles are not seen. I now should look like one triangle. Now fold one side down so it make two smaller triangles. Do the same on the other side. Bring the wings up a bit and throw!

you have to turn one flap up and the other one down to get your paper airplane to do a barell roll

u don't because if it's made out of paper it's not made out of popsicle sticks.

a paper clip wheighs about 3 kilograms

catching air

The wing of the paper airplane can make it fly far. For a glider, make a large wingspan and light, evenly balanced weight. Also, the wider the wings are the easier it will be to gain lift and the more narrower the wings are the harder it will be to stay in the air longer.

The impact origami had on china when it first stared was that every one in the world would pay mad money to get there hands on origami

Depends on where you launched it from. If you threw it from ground level and it landed on ground of equal height, then I'd say 15 seconds, 30 at the absolute max. If you launched it from, say, 30,000 feet, the altitude at which jumbo jets fly, then who knows how long it could stay up there, let alone where it will land.

As many as you want.

As many as you want.

As many as you want.

As many as you want.

Mountian folds are folds with two folds down and one fold up see oragami folding category see diagram under to left pionting up like a mountain or a inverted (V) shape in a triangular shape and angled strait across from [B1] IN A 52-0 DEGREE ANGLE SO PIONT (A) PERTRUDES UP HORIZONTALY

____________

[A]UP

__[B1]DOWN[B2]

it is 5000 feet long