Air pressure does not come into play with most model rockets.
it pushes the rocket into the air to make it go higher.
A popular rocket toy name is the "Stomp Rocket." It is a toy rocket launcher that uses air pressure to propel foam rockets into the air when stomped on.
1:2
The rocket might explode from the added pressure when the combustion reaction hits the air.
the barometric pressure
300-600
The amount of exposed surface area of the fuel
the pressure in side the balloon will get squizz out and make the air move
It's a government conspiracy
The rocket might explode from the added pressure when the combustion reaction hits the air pocket. - apex
What kind of rocket? A rocket you could make would use mainly compressed air A NASA rocket, would use a LOT of gasoline to propel it into the air.
The air pressure would reduce.