What would happen if a commercial aircraft flew into space?

It would promptly crash into the nearest asteroid. Commercial aircraft don't have those photon cannons like the little spaceship in the game does, so the asteroids would surely destroy it.

A commecial aircraft would not make it into space as it would not get out of the upper atmosphere before blowing up.

the world would explode. No, really. It couldnt. Once it gets high enough the air gets to thin to fly on. But, if it COULD.... everyone would run out of oxygen ,freeze, implode and be killed by radiation at the same time.

It can't happen. It doesn't carry enough fuel or have enough thrust to break out of Earth's gravity. Also, There is no oxygen when you get high up so the engines wouldn't work. Assuming you overcame these, you would then have to worry about reentry as regular planes have no heat sheilds to protect them from the friction/heat when coming back into Earth.

It cant but it would burn up on reentry .

I assume you're talking about a 747 or some type of airliner. First, I don't believe it would be able to make it there. It's engines would die from a lack of oxygen at a lower altitude. But if it somehow made it, the plane would eventually fall back to earth and probably disintegrate on the way back in. It may also explode in space due to it's pressurized cabin, or maybe the air would simply leak out.

For that to happen the laws of physics would have had to have changed since jet engines won't work above a certain altitude due to the lack of oxygen. If we assume a miracle, then the airlines legal department would have serious problems and their insurance company would be paying a few hundred million dollars in claims. Physicists around the world would get very excited. A blue ribbon commission would be appointed to study how an impossible event could occur.

Even a pressurized aircraft is not air tight. It depends on the engines constantly compressing the air around it and feeding it into the cabin. So in a vacuum it would depressurize. And of course the engines would stop for lack of air and the wings would not provide any lift for lack of air and the control surfaces would not provide any control for lack of air.

it will burn before getting out of the stratosphere.

No runway or airports at planets other than earth

The plane would not burn out going out, it will burn on re-entry. But, the people inside will get a severe case of the benz. Like when you submerge deep underwater and then come up too quickly. The fuselage is air tight and pressurized so it might just cave in or explode or something because of the difference.