Hint :
All helicopters and levels:
To get all helicopters and levels just put in R, C-Left, Right, Up in the password screen.

Level Passwords:
02 - Up, Down, Left, Right
03 - Up, Down, Left, Up
04 - Down, Up, Left, Right
05 - Down, Up, Left, Down
06 - Down, Up, Right, Down
07 - Left, Down, L, Up
08 - Left, Down, L, Down
09 - Left, Up, L, Down
10 - L, Up, Left, Down
11 - L, Up, Left, Up
12 - L, Up, L, Down
13 - L, Down, Up, Left
14 - R, C-Left, Up, Right
15 - C-Down, L, Down, Down
16 - R, C-Left, Right, Up