The "invincible aircraft" setting is available in the controls. When this is
on,  pressing control-tab will add 500 feet to your altitude.

While in flight (or after you die), you can hit + s to go into slow mode.
You start out in the exact geographic center of the island. No hit + x to
turn on your joystick. Now, you can move (point)with your stick. Here
are the keys:

                  8 -- hit _ repeatedly _ to go forward
                  2 -- hit _ repeatedly _ to go backwards
                  4 -- hit _ repeatedly _ to go left
                  6 -- hit _ repeatedly _ to go right
                  7 -- hit _ repeatedly _ to go up
                  1 -- hit _ repeatedly _ to go down

The trigger fires the cannon (toned-down for some reason)and fires
heavily toned-down mavericks.

Now you can visit the baseball field in Havana, the hole in the wall,
or complete the mission after you die.